55 results on '"Jean-Baptiste Moussy"'
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2. Engineering the magnetic coupling and anisotropy at the molecule–magnetic surface interface in molecular spintronic devices
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Victoria E. Campbell, Monica Tonelli, Irene Cimatti, Jean-Baptiste Moussy, Ludovic Tortech, Yannick J. Dappe, Eric Rivière, Régis Guillot, Sophie Delprat, Richard Mattana, Pierre Seneor, Philippe Ohresser, Fadi Choueikani, Edwige Otero, Florian Koprowiak, Vijay Gopal Chilkuri, Nicolas Suaud, Nathalie Guihéry, Anouk Galtayries, Frederic Miserque, Marie-Anne Arrio, Philippe Sainctavit, and Talal Mallah
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Science - Abstract
Controlling the magnetic response of a molecular device is important for spintronic applications. Here the authors report the self-assembly, magnetic coupling, and anisotropy of two transition metal complexes bound to a ferrimagnetic surface, and probe the role of the nature of the transition metal ion.
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- 2016
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3. Widely tunable two-colour seeded free-electron laser source for resonant-pump resonant-probe magnetic scattering
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Eugenio Ferrari, Carlo Spezzani, Franck Fortuna, Renaud Delaunay, Franck Vidal, Ivaylo Nikolov, Paolo Cinquegrana, Bruno Diviacco, David Gauthier, Giuseppe Penco, Primož Rebernik Ribič, Eleonore Roussel, Marco Trovò, Jean-Baptiste Moussy, Tommaso Pincelli, Lounès Lounis, Michele Manfredda, Emanuele Pedersoli, Flavio Capotondi, Cristian Svetina, Nicola Mahne, Marco Zangrando, Lorenzo Raimondi, Alexander Demidovich, Luca Giannessi, Giovanni De Ninno, Miltcho Boyanov Danailov, Enrico Allaria, and Maurizio Sacchi
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Science - Abstract
Two-colour X-ray free electron laser is a powerful tool for pump–probe measurements, but currently constrained by limited tunability. Here, Ferrari et al. develop a configuration that allows tuning both the pump and the probe to specific electronic excitations, providing element selectivity.
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- 2016
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4. Element Selective Probe of the Ultra-Fast Magnetic Response to an Element Selective Excitation in Fe-Ni Compounds Using a Two-Color FEL Source
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Eugenio Ferrari, Carlo Spezzani, Franck Fortuna, Renaud Delaunay, Franck Vidal, Ivaylo Nikolov, Paolo Cinquegrana, Bruno Diviacco, David Gauthier, Giuseppe Penco, Primož Rebernik Ribič, Eléonore Roussel, Mauro Trovò, Jean-Baptiste Moussy, Tommaso Pincelli, Lounès Lounis, Cristian Svetina, Marco Zangrando, Nicola Mahne, Lorenzo Raimondi, Michele Manfredda, Emanuele Pedersoli, Flavio Capotondi, Alexander Demidovich, Luca Giannessi, Maya Kiskinova, Giovanni De Ninno, Miltcho Boyanov Danailov, Enrico Allaria, and Maurizio Sacchi
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free electron laser ,two-color source ,ultra-fast dynamics ,Applied optics. Photonics ,TA1501-1820 - Abstract
The potential of the two-color mode implemented at the FERMI free-electron laser (FEL) source for pumping and probing selectively different atomic species has been demonstrated by time-resolved scattering experiments with permalloy (FeNi alloy) and NiFe2O4 samples. We monitored the ultra-fast demagnetization of Ni induced by the pump FEL pulse, by tuning the linearly-polarized FEL probe pulse to the Ni-3p resonance and measuring the scattered intensity in the transverse magneto-optical Kerr effect geometry. The measurements were performed by varying the intensity of the FEL pump pulse, tuning its wavelength to and off of the Fe-3p resonance, and by spanning the FEL probe pulse delays across the 300–900 fs range. The obtained results have evidenced that for the case of NiFe2O4, there is a sensible difference in the magnetic response at the Ni site when the pump pulse causes electronic excitations at the Fe site.
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- 2017
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5. Band unfolding with a general transformation matrix: From code implementation to interpretation of photoemission spectra.
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Oleg Rubel, Jean-Baptiste Moussy, Paul Foulquier, and Véronique Brouet
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- 2023
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6. Stoichiometry driven tuning of physical properties in epitaxial Fe3-Cr O4 thin films
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Pâmella Vasconcelos Borges Pinho, Alain Chartier, Denis Menut, Antoine Barbier, Myrtille O.J.Y. Hunault, Philippe Ohresser, Cécile Marcelot, Bénédicte Warot-Fonrose, Frédéric Miserque, and Jean-Baptiste Moussy
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General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Surfaces, Coatings and Films - Published
- 2023
7. Stoichiometry Driven Tuning of Physical Properties in Epitaxial Fe3-Xcrxo4 Thin Films
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Pâmella Vasconcelos Borges Pinho, Alain Chartier, Denis Menut, Antoine Barbier, Myrtille O.J.Y. Hunault, Philippe Ohresser, Cécile Marcelot, Bénédicte Warot-Fonrose, Frédéric Miserque, and Jean-Baptiste Moussy
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
8. Crystal field effects on the photoemission spectra in Cr2O3 thin films: from multiplet splitting features to the local structure
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Pâmella Vasconcelos Borges Pinho, Frédéric Miserque, Jean-Baptiste Moussy, Alain Chartier, Denis Menut, Laboratoire de Modélisation, Thermodynamique et Thermochimie (LM2T), Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME), Département de Physico-Chimie (DPC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département de Physico-Chimie (DPC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
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010302 applied physics ,[PHYS]Physics [physics] ,050208 finance ,Materials science ,05 social sciences ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular physics ,Spectral line ,Crystal ,Transition metal ,Atomic orbital ,X-ray photoelectron spectroscopy ,0502 economics and business ,0103 physical sciences ,General Materials Science ,050207 economics ,Thin film ,0210 nano-technology ,Multiplet ,Envelope (waves) - Abstract
International audience; Changes in the shape of X-ray photoemission (XPS) spectra can be related to changes in the local structure of a transi-tion metal. By combining Crystal Field Multiplet calculations and well-controlled molecular beam epitaxy growth of alpha-Cr2O3(0001) thin films on alpha-Al2O3(0001) substrates, we prove that it possible to link the features of Cr 2p XPS spectra with local distortions of CrO6 octahedra and d-orbitals reorganization. Hence, we show that the splitting of the Cr 2p3/2 envelope is related to the degeneracy of the t2g orbital triplet, which corresponds to a fully relaxed structure. Conversely, the broad unstructured Cr 2p3/2 envelope relies on splitting of t2g orbitals and it is the fingerprint of large trigonal distor-tions of CrO6 octahedra. Then, using the Cr 2p XPS as a structural tool for -Cr2O3, we show that the Cr2O3 protective layer formed by oxidation of polycrystalline Ni30Cr alloy exhibits in-plane strains at early oxidation stages and grows preferentially along the c-axis.
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- 2020
9. Mn 0.7 Fe 2.3 O 4 Nanoplatelets Embedded in BaTiO 3 Perovskite Thin Films for Multifunctional Composite Barriers
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Phuong-Linh Nguyen, Alina Vlad, Jocelyne Leroy, Andrea Resta, Rachid Belkhou, Cristian Mocuta, D. Stanescu, Hélène Magnan, Brice Sarpi, Antoine Barbier, Philippe Ohresser, Jean-Baptiste Moussy, Edwige Otero, N. Jedrecy, Federico Petronio, Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Ile-de-France: C'Nano IdF, ISCPIF, DIM OxyMore and DIM nanoK, C'nano Ile de France, ANR-15-CE09-0005,IOBTO,Etudes in operando de nanostructures d'oxydes multiferroiques à base de titanate de baryum(2015), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,ComputingMethodologies_MISCELLANEOUS ,Composite number ,Nanotechnology ,02 engineering and technology ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0103 physical sciences ,General Materials Science ,Multiferroics ,Thin film ,010306 general physics ,0210 nano-technology ,Hardware_REGISTER-TRANSFER-LEVELIMPLEMENTATION ,Perovskite (structure) - Abstract
International audience; Multifunctional materials having the ability to respond to various external fields are tremendously sought; not only for their potential use as sensing components for devices, but also because they provide an elegant way to optimize materials usage. However, multifunctional single-phase materials are scarce and one approach to overcome this problem is to build artificial compounds combining different properties. This is a challenging materials science task, especially when two-dimensional structures are considered. In this paper, we report on the successful realization of multifunctional systems consisting of ferrimagnetic Mn0.7Fe2.3O4 spinel platelets, of controlled sizes and nanometric thicknesses, embedded in an epitaxial ferroelectric BaTiO3 perovskite thin film. The embedded platelets experience a much higher isostatic strain than that obtained for single layers. We successfully achieved nanometer-thick composite layers, with identical composition, having either in plane or out of plane electric polarization orientations. The optimal samples combine several functionalities: (i) the magnetoelectric nature of the full oxide artificial structures is confirmed; (ii) semiconducting diode behaviors are obtained when contacted with a metal electrode and (iii) marked (8 fold) electro-resistance transport properties with respect to the electric polarization orientation are revealed. The embedded platelets configuration enhances significantly interface and two-dimensional effects and is thus believed of high interest to realize functional device structures.
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- 2019
10. Electrostriction, Electroresistance and Electromigration in Epitaxial BaTiO3 - based Heterostructures: Role of Interfaces and Electric Poling
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Antoine Barbier, D. Stanescu, Brice Sarpi, Thomas Aghavnian, Cindy L. Rountree, Jean-Baptiste Moussy, Hélène Magnan, Maxime Rioult, Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), and Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes (SPHYNX)
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Materials science ,electric poling ,7. Clean energy ,Electromigration ,topography deformation ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,barium titanate ,General Materials Science ,ComputingMilieux_MISCELLANEOUS ,memristor effect ,Electrostriction ,Spintronics ,Ferroelectric materials ,business.industry ,Poling ,Heterojunction ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Ferroelectricity ,piezoresponse force microscopy PFM ,Piezoresponse force microscopy ,chemistry ,Barium titanate ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Optoelectronics ,Kelvin probe force microscopy KPFM ,business ,ferroelectric thin films - Abstract
Ferroelectric materials hold significant promise for potential applications in a number of fields including spintronics and solar energy harvesting. When integrating them into heterostructures, it ...
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- 2019
11. Controlling the magnetic exchange coupling in hybrid heterojunctions via spacer layers of π -conjugated molecules
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Alexander Smogunov, Pierre Bonville, Camille Blouzon, Dongzhe Li, Ludovic Tortech, Jean-Baptiste Moussy, Quentin Arnoux, Yannick J. Dappe, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Chimie Moléculaire de Paris Centre (FR 2769), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Groupe Modélisation et Théorie (GMT), RTRA 'triangle de la Physique': project HeteroSpinMol, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Service de physique de l'état condensé (SPEC - UMR3680), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
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Coupling ,Materials science ,Condensed matter physics ,Spintronics ,Heterojunction ,02 engineering and technology ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Inductive coupling ,Magnetization ,Condensed Matter::Materials Science ,Ferromagnetism ,Ab initio quantum chemistry methods ,Condensed Matter::Superconductivity ,0103 physical sciences ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Antiferromagnetism ,010306 general physics ,0210 nano-technology - Abstract
Mastering and understanding the magnetic couplings between magnetic electrodes separated by organic layers are crucial for developing new hybrid spintronic devices. We study the magnetic exchange interactions in organic-inorganic heterojunctions and unveil the possibility of controlling the strength of the magnetic exchange coupling between two ferromagnetic electrodes across $\ensuremath{\pi}$-conjugated molecules' ($\ensuremath{\alpha}$-sexithiophene or para-sexiphenyl) ultrathin film. In $\mathrm{F}{\mathrm{e}}_{3}{\mathrm{O}}_{4}/\ensuremath{\pi}$-conjugated molecules/Co magnetic tunnel junctions, an antiferromagnetic interlayer exchange coupling with variable strength is observed according to the nature of the aromatic rings (thiophene or phenyl groups). The underlying physical mechanism is revealed by ab initio calculations relating the strength of magnetic coupling to the spin moment penetration into a molecular layer at the molecule/Co interface. The prospect that magnetic coupling between two ferromagnetic electrodes can be mediated and tuned by organic molecules opens different perspectives in the way magnetization of organic tunnel junctions or spin valves can be driven.
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- 2019
12. Cross-Correlation between Strain, Ferroelectricity, and Ferromagnetism in Epitaxial Multiferroic CoFe
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Nathalie, Jedrecy, Thomas, Aghavnian, Jean-Baptiste, Moussy, Hélène, Magnan, Dana, Stanescu, Xavier, Portier, Marie-Anne, Arrio, Cristian, Mocuta, Alina, Vlad, Rachid, Belkhou, Philippe, Ohresser, and Antoine, Barbier
- Abstract
Multiferroic biphase systems with robust ferromagnetic and ferroelectric response at room temperature would be ideally suitable for voltage-controlled nonvolatile memories. Understanding the role of strain and charges at interfaces is central for an accurate control of the ferroelectricity as well as of the ferromagnetism. In this paper, we probe the relationship between the strain and the ferromagnetic/ferroelectric properties in the layered CoFe
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- 2018
13. Cross-Correlation between Strain, Ferroelectricity, and Ferromagnetism in Epitaxial Multiferroic CoFe 2 O 4 /BaTiO 3 Heterostructures
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Antoine Barbier, Philippe Ohresser, Rachid Belkhou, Cristian Mocuta, Alina Vlad, N. Jedrecy, Xavier Portier, Jean-Baptiste Moussy, M.-A. Arrio, Thomas Aghavnian, Hélène Magnan, D. Stanescu, Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), and Normandie Université (NU)
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[PHYS]Physics [physics] ,Materials science ,Condensed matter physics ,Magnetic circular dichroism ,multiferroics ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,X-ray absorption ,0104 chemical sciences ,Magnetization ,Piezoresponse force microscopy ,strain ,Ferromagnetism ,X-ray magnetic circular dichroism ,Ferrimagnetism ,General Materials Science ,Multiferroics ,oxide interface ,0210 nano-technology ,ferrimagnetism ,ferroelectric polarization - Abstract
International audience; Multiferroic biphase systems with robust ferromagnetic and ferroelectric response at room temperature would be ideally suitable for voltage-controlled nonvolatile memories. Understanding the role of strain and charges at interfaces is central for an accurate control of the ferroelectricity as well as of the ferromagnetism. In this paper, we probe the relationship between the strain and the ferromagnetic/ferroelectric properties in the layered CoFe2O4/BaTiO3 (CFO/BTO) model system. For this purpose, ultrathin epitaxial bilayers, ranging from highly strained to fully relaxed, were grown by molecular beam epitaxy on Nb:SrTiO3(001). The lattice characteristics, determined by X-ray diffraction, evidence a non-intuitive cross-correlation: the strain in the bottom BTO layer depends on the thickness of the top CFO layer and vice versa. Plastic deformation participates in the relaxation process through dislocations at both interfaces, revealed by electron microscopy. Importantly, the switching of the BTO ferroelectric polarization, probed by piezoresponse force microscopy, is found dependent on the CFO thickness: the larger is the latter, the easiest is the BTO switching. In the thinnest thickness regime, the tetragonality of BTO and CFO has a strong impact on the 3d electronic levels of the different cations, which were probed by X-ray linear dichroism. The quantitative determination of the nature and repartition of the magnetic ions in CFO, as well as of their magnetic moments, has been carried out by X-ray magnetic circular dichroism, with the support of multiplet calculations. While bulklike ferrimagnetism is found for 5-15 nm thick CFO layers with a magnetization resulting as expected from the Co2+ ions alone, important changes occur at the interface with BTO over a thickness of 2-3 nm because of the formation of Fe2+ and Co3+ ions. This oxidoreduction process at the interface has strong implications concerning the mechanisms of polarity compensation and coupling in multiferroic heterostructures.
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- 2018
14. Investigating magnetic proximity effects at ferrite/Pt interfaces
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Frédéric Petroff, Stéphane Collin, Jean-Baptiste Moussy, Andrei Rogalev, Vicent Cros, Richard Mattana, F. Wilhelm, Abdelmadjid Anane, Cyrile Deranlot, Manuel Collet, Katharina Ollefs, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, European Synchrotron Radiation Facility (ESRF), and Centre National de la Recherche Scientifique (CNRS)-THALES
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[PHYS]Physics [physics] ,Materials science ,Physics and Astronomy (miscellaneous) ,Magnetic domain ,Spintronics ,Condensed matter physics ,Yttrium iron garnet ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferromagnetic resonance ,Magnetic susceptibility ,chemistry.chemical_compound ,Condensed Matter::Materials Science ,Nuclear magnetic resonance ,Ferromagnetism ,Magnetic shape-memory alloy ,chemistry ,Magnet ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology - Abstract
International audience; Spintronic devices based on pure spin currents have drawn a lot of attention during the last few years for low energy device design. One approach to generate pure spin currents is to combine a metallic or insulating ferromagnetic layer with a non-magnetic metallic layer with a large spin-orbit coupling. A recent controversy has arisen in the possible role of magnetic proximity effects at ferromagnetic/ non-magnetic interfaces, which can hamper the understanding of pure spin current generation mechanisms. While magnetic proximity effects have been frequently observed at ferromagnetic metal/non-magnetic interfaces, there are only a few studies on ferromagnetic insulator/non-magnetic interfaces. Regarding the use of ferromagnetic insulators, the focus has been mainly on yttrium iron garnet (YIG). However, investigation of induced magnetic moments at YIG/Pt interfaces has engendered contradictory results. Here, we propose to study insulating ferrites for which electronic and magnetic properties can be modulated. Magnetic proximity effects have been investigated at MnFe 2 O 4 /Pt, CoFe 2 O 4 /Pt, and NiFe 2 O 4 /Pt interfaces by X-ray circular magnetic dichroism (XMCD) measurements at the Pt L 3 edge. Although hybridization with Pt seems to be different among the ferrites, we do not detect any XMCD signal as the signature of an induced magnetism in Pt. We have then studied the Fe 3 O 4 ferrite below and above the Verwey transition temperature. No XMCD signal has been measured in the insulating or conducting phase of Fe 3 O 4. This suggests that the absence of magnetic proximity effects at ferrite/Pt interfaces is not linked to the insulating character or not of the ferrites.
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- 2017
15. Crystal Growth and Characterization of HgBa
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Bastien, Loret, Anne, Forget, Jean-Baptiste, Moussy, Sylvie, Poissonnet, Patrick, Bonnaillie, Gaston, Collin, Pierre, Thuéry, Alain, Sacuto, and Dorothée, Colson
- Abstract
We report an original procedure for the elaboration of very high-quality single crystals of superconducting HgBa
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- 2017
16. Crystal Growth and Characterization of HgBa2Ca2Cu3O8+δ Superconductor with the Highest Critical Temperature at Ambient Pressure
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Patrick Bonnaillie, Dorothée Colson, Jean-Baptiste Moussy, B. Loret, Pierre Thuéry, Alain Sacuto, Sylvie Poissonnet, Anne Forget, G. Collin, Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Service de recherches de métallurgie physique (SRMP), Département des Matériaux pour le Nucléaire (DMN), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Moléculaire et de Catalyse pour l'Energie (ex LCCEF) (LCMCE), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), DIM OXYMORE, CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Superconductivity ,Condensed matter physics ,Chemistry ,Annealing (metallurgy) ,Doping ,Crystal growth ,02 engineering and technology ,Crystal structure ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Inorganic Chemistry ,Condensed Matter::Superconductivity ,0103 physical sciences ,Cuprate ,Condensed Matter::Strongly Correlated Electrons ,Physical and Theoretical Chemistry ,010306 general physics ,0210 nano-technology ,Spectroscopy ,Phase diagram - Abstract
International audience; We report an original procedure for the elaboration of very high quality single crystals of superconducting HgBa2Ca2Cu3O8+δ mercury cuprates. These single crystals are unique with very high quality surface paving the way for spectroscopic, transport and thermodynamic probes in order to understand the hole-doped cuprate phase diagram. The superconductivity transition width of about 2 K indicates they are homogeneous. Annealing allows to optimize Tc up to Tc max = 133 K. We show for the first time that with adequate heat treatment, Hg-1223 can be largely under-doped and its doping level controlled. Importantly, the crystal structure was studied in detail by single crystal X-ray diffraction, and we have identified the signature of the under-doping by a detailed sample characterization and micro-Raman spectroscopy measurements.
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- 2017
17. Element Selective Probe of the Ultra-Fast Magnetic Response to an Element Selective Excitation in Fe-Ni Compounds Using a Two-Color FEL Source
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Giuseppe Penco, Carlo Spezzani, Emanuele Pedersoli, Enrico Allaria, Primož Rebernik Ribič, Alexander Demidovich, Miltcho B. Danailov, Ivaylo Nikolov, Eugenio Ferrari, Cristian Svetina, Luca Giannessi, Jean-Baptiste Moussy, Marco Zangrando, Maya Kiskinova, Franck Vidal, Michele Manfredda, Mauro Trovò, Renaud Delaunay, David Gauthier, Eléonore Roussel, Maurizio Sacchi, Franck Fortuna, Flavio Capotondi, Giovanni De Ninno, Lounès Lounis, Paolo Cinquegrana, Bruno Diviacco, Nicola Mahne, Tommaso Pincelli, Lorenzo Raimondi, Dipartimento di Fisica [Trieste], Università degli studi di Trieste, Elettra Sincrotrone Trieste, Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Chimie Physique - Matière et Rayonnement (LCPMR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Croissance et propriétés de systèmes hybrides en couches minces (INSP-E8), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Dipartimento di Fisica (Milano), Università degli Studi di Milano [Milano] (UNIMI), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL), Italian National agency for new technologies, Energy and sustainable economic development [Frascati] (ENEA), Laboratory of Quantum Optics, University of Nova Gorica, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), European Project: 312284,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2012-1,CALIPSO(2012), European Project: PEPS SASLELX, Università degli studi di Trieste = University of Trieste, Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Milano = University of Milan (UNIMI), École normale supérieure - Paris (ENS-PSL), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
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Permalloy ,lcsh:Applied optics. Photonics ,Materials science ,Kerr effect ,Physics::Optics ,02 engineering and technology ,free electron laser ,01 natural sciences ,law.invention ,Optics ,law ,0103 physical sciences ,Radiology, Nuclear Medicine and imaging ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,010306 general physics ,Instrumentation ,two-color source ,Scattering ,business.industry ,Free-electron laser ,Resonance ,lcsh:TA1501-1820 ,021001 nanoscience & nanotechnology ,Laser ,Atomic and Molecular Physics, and Optics ,Pulse (physics) ,Wavelength ,Physics::Accelerator Physics ,Atomic physics ,0210 nano-technology ,business ,ultra-fast dynamics - Abstract
The potential of the two-color mode implemented at the FERMI free-electron laser (FEL) source for pumping and probing selectively different atomic species has been demonstrated by time-resolved scattering experiments with permalloy (FeNi alloy) and NiFe 2 O 4 samples. We monitored the ultra-fast demagnetization of Ni induced by the pump FEL pulse, by tuning the linearly-polarized FEL probe pulse to the Ni-3p resonance and measuring the scattered intensity in the transverse magneto-optical Kerr effect geometry. The measurements were performed by varying the intensity of the FEL pump pulse, tuning its wavelength to and off of the Fe-3p resonance, and by spanning the FEL probe pulse delays across the 300–900 fs range. The obtained results have Photonics 2017, 4, 6 2 of 10 evidenced that for the case of NiFe 2 O 4 , there is a sensible difference in the magnetic response at the Ni site when the pump pulse causes electronic excitations at the Fe site.
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- 2017
- Full Text
- View/download PDF
18. Engineering the magnetic coupling and anisotropy at the molecule–magnetic surface interface in molecular spintronic devices
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Frédéric Miserque, Victoria E. Campbell, Marie-Anne Arrio, Nicolas Suaud, Ludovic Tortech, Richard Mattana, Yannick J. Dappe, Philippe Ohresser, Talal Mallah, Pierre Seneor, Fadi Choueikani, Anouk Galtayries, Irene Cimatti, Régis Guillot, Edwige Otero, Monica Tonelli, Philippe Sainctavit, Nathalie Guihéry, Jean-Baptiste Moussy, Eric Rivière, Vijay Gopal Chilkuri, Florian Koprowiak, Sophie Delprat, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Systèmes étendus et magnétisme (LCPQ) (SEM), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Recherche de Chimie Paris (IRCP), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Laboratoire d'Etude de la Corrosion Aqueuse (LECA), Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME), Département de Physico-Chimie (DPC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département de Physico-Chimie (DPC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-THALES [France], Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ministère de la Culture (MC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), THALES-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Centre National de la Recherche Scientifique (CNRS)-THALES, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)
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Surface (mathematics) ,Materials science ,Science ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Condensed Matter::Materials Science ,Transition metal ,Ferrimagnetism ,Molecule ,Anisotropy ,ComputingMilieux_MISCELLANEOUS ,Multidisciplinary ,Spintronics ,Condensed matter physics ,General Chemistry ,equipment and supplies ,021001 nanoscience & nanotechnology ,Inductive coupling ,Transition metal ions ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,human activities - Abstract
A challenge in molecular spintronics is to control the magnetic coupling between magnetic molecules and magnetic electrodes to build efficient devices. Here we show that the nature of the magnetic ion of anchored metal complexes highly impacts the exchange coupling of the molecules with magnetic substrates. Surface anchoring alters the magnetic anisotropy of the cobalt(II)-containing complex (Co(Pyipa)2), and results in blocking of its magnetization due to the presence of a magnetic hysteresis loop. In contrast, no hysteresis loop is observed in the isostructural nickel(II)-containing complex (Ni(Pyipa)2). Through XMCD experiments and theoretical calculations we find that Co(Pyipa)2 is strongly ferromagnetically coupled to the surface, while Ni(Pyipa)2 is either not coupled or weakly antiferromagnetically coupled to the substrate. These results highlight the importance of the synergistic effect that the electronic structure of a metal ion and the organic ligands has on the exchange interaction and anisotropy occurring at the molecule–electrode interface., Controlling the magnetic response of a molecular device is important for spintronic applications. Here the authors report the self-assembly, magnetic coupling, and anisotropy of two transition metal complexes bound to a ferrimagnetic surface, and probe the role of the nature of the transition metal ion.
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- 2016
19. From ensemble average to single (nano-) objects properties by X-ray microdiffraction: a short review on structure determination (local strain, composition, ...) and objects manipulation (AFM-coupled)
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Ana Diaz, A. V. Ramos, Mário Rodrigues, Th. Scheller, R. Paniago, Cristian Mocuta, Frédéric Petroff, Antoine Barbier, J. Chevrier, J. Stangl, Bärbel Krause, G. Bauer, Richard Mattana, Angelo Malachias, T. H. Metzger, Thomas W. Cornelius, K. Mundboth, Cyrile Deranlot, Stefan Stanescu, O. Dhez, M.-J. Guittet, and Jean-Baptiste Moussy
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Diffraction ,Coupling ,Materials science ,Nanostructure ,business.industry ,Dispersity ,Resolution (electron density) ,Metals and Alloys ,Condensed Matter Physics ,Sample (graphics) ,Signal ,Optics ,Nano ,Materials Chemistry ,Physical and Theoretical Chemistry ,business - Abstract
In standard diffraction experiments, ensembles of objects are characterized yielding averaged, statistical properties (meaningful only if the ensemble is monodisperse). Focused x-ray beams are used here to localize single nanostructures, identifying and probing individual objects one by one. In a scanning mode, a 2-dimensional image of the sample is recorded, which allows the reproducible alignment of a specific nanostructure for analysis. The x-ray scattered signal is analyzed and modelled, to give access to the shape, strain and composition inside the single object with sub-micron resolution. Combination of x-ray microdiffraction technique with other micro-probe experiments on the very same individual object (simultaneous coupling of x-ray diffraction measurements with atomic force microscopy (AFM)) is also shown; we prove the possibility to interact with the objects and to address elastic properties for individual nano-structures out of an ensemble.
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- 2010
20. Crystalline structure of oxide-based epitaxial tunnel junctions
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Frédéric Petroff, Antoine Barbier, Stefan Stanescu, Cyrile Deranlot, Jean-Baptiste Moussy, Richard Mattana, M.-J. Guittet, Christophe Gatel, A. V. Ramos, and Cristian Mocuta
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Diffraction ,Materials science ,business.industry ,Oxide ,General Physics and Astronomy ,Crystal structure ,Epitaxy ,law.invention ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Tunnel effect ,Optics ,chemistry ,Tunnel junction ,law ,Optoelectronics ,General Materials Science ,Physical and Theoretical Chemistry ,Photolithography ,business ,Lithography - Abstract
Epitaxial metal/oxide based magnetic tunnel-junctions (MTJ) are valuable model systems to investigate the influence of the crystallinity of individual layers on the magnetic properties. We have non-destructively studied the effect of the optical lithography procedure on the crystalline structure of MTJ’s with lateral spatial resolution by performing local x-ray diffraction experiments using a microfocused x-ray spot. We demonstrate that the lithography process produces distortion effects on the crystalline structure of the layers near the edges of the lithographed junction. These distortions are present on all the constituent layers and are most probably driven by the elastic constants of the materials. They translate into tilts of the crystalline planes in the vicinity of the edges and propagate towards the center of the junction; the tilt’s amplitude (up to several degrees) and sign (concave or convex) depend on the junction’s shape, size and the type of materials (interfaces) used. We report results for junctions made with two types of metal-oxide interfaces (Co/CoFe2O4 and Co/Fe3O4), with sizes from 10 to 150 μm and various shapes (square-, rectangle- and disk-like).
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- 2009
21. Determination of the cation site distribution of the spinel in multiferroic CoFe2O4 / BaTiO3 layers by X-ray photoelectron spectroscopy
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R. Belkhou, Hélène Magnan, Jean-Baptiste Moussy, M.-A. Arrio, Ph. Sainctavit, Antoine Barbier, Philippe Ohresser, D. Stanescu, N. Jedrecy, T. Aghavnian, Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)
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[PHYS]Physics [physics] ,Radiation ,Magnetic circular dichroism ,Chemistry ,Spinel ,Analytical chemistry ,X-ray photoelectron spectroscopy (XPS) ,Oxides ,Crystal structure ,Cation distribution ,engineering.material ,X-ray magnetic circular dichroism (XMCD) ,Condensed Matter Physics ,Epitaxy ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Octahedron ,X-ray photoelectron spectroscopy ,engineering ,Ferrites ,Multiferroics ,Physical and Theoretical Chemistry ,Spectroscopy ,Stoichiometry - Abstract
International audience; The properties of CoFe2O4/BaTiO3 artificial multiferroic multilayers strongly depend on the crystalline structure, the stoichiometry and the cation distribution between octahedral (Oh) and tetrahedral (Td) sites (inversion factor). In the present study, we have investigated epitaxial CoFe2O4 layers grown on BaTiO3, with different Co/Fe ratios. We determined the cation distribution in our samples by X-ray magnetic circular dichroism (XMCD), a well accepted method to do so, and by X-ray photoelectron spectroscopy (XPS), using a fitting method based on physical considerations. We observed that our XPS approach converged on results consistent with XMCD measurements made on the same samples. Thus, within a careful decomposition based on individual chemical environments it is shown that XPS is fully able to determine the actual inversion factor.
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- 2015
22. Experimental evidence of the spin-dependence of electrons reflections in magnetic multilayers
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Jean-Baptiste Moussy, Ch. Gatel, R. Serra, M. Pannetier, J.C. Ousset, M. Gautier-Soyer, Etienne Snoeck, and A. Bataille
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Materials science ,Condensed matter physics ,Magnetoresistance ,Scattering ,Mechanical Engineering ,Giant magnetoresistance ,Condensed Matter Physics ,Thermal conduction ,Interfacial Phenomenon ,Magnetization ,Mechanics of Materials ,Ferrimagnetism ,Ferrite (magnet) ,General Materials Science - Abstract
The giant magnetoresistance (GMR) of multilayers in the current in plane (CIP) geometry can be understood by considering the spin-dependent scattering effects within the magnetic layers and at the non-magnetic/magnetic interfaces. In this paper we experimentally put on view the magnetoresistance effect created only by the spin-dependent reflection of electrons at the interfaces. Two epitaxial systems were studied, consisting of two ferrimagnetic insulators layers at low temperature (CoFe2O4 and Fe3O4) separated by a non-magnetic metallic layer (M = Au or Pt). The transport properties indicate that conduction of the CoFe2O4/M/Fe3O4 trilayers take place within the thin metallic layer. An optimal magnetoresistance up to 5% at 10 K associated to the switching from parallel to anti-parallel configuration of the magnetization of the two ferrite layers has been obtained. It is associated to the spin-dependent interfacial scattering contribution of the CIP-GMR. The augmentation of the GMR when decreasing the metallic layer thickness or increasing the oxide layers width confirms this GMR is essentially an interfacial phenomenon. The Pt-based system shows an additional Anisotropic Magnetoresistance (AMR), which is not evidenced in the Au-based trilayer. We suggest that this AMR comes from the polarization of the Pt layer by the ferrimagnetic oxides.
- Published
- 2006
23. Study of the electronic paraprocess and antiphase boundaries as sources of the demagnetisation phenomenon in magnetite
- Author
-
M. Gautier-Soyer, M.-J. Guittet, S. Gota, F. Delille, C. Marin, B. Dieny, and Jean-Baptiste Moussy
- Subjects
Materials science ,Condensed matter physics ,Condensed Matter Physics ,Epitaxy ,Crystallographic defect ,Electronic, Optical and Magnetic Materials ,Crystal ,Magnetization ,chemistry.chemical_compound ,Charge ordering ,Nuclear magnetic resonance ,chemistry ,Thin film ,Saturation (magnetic) ,Magnetite - Abstract
In this paper, a detailed study of the magnetic behaviour particularly at the Verwey transition is presented for some stoichiometric magnetite samples, as a function of their shape (film/bulk) and crystalline structure (single/polycrystal). Travelling solvent floating zone technique was first used to obtain crystalline bulk magnetite samples (1 1 0) oriented, while molecular beam epitaxy allowed us to grow a 68 nm Fe 3 O 4 (1 1 1) crystalline film on α -Al 2 O 3 (0 0 0 1) substrate. A 64 nm Fe 3 O 4 polycrystalline film grown on an Si/SiO 2 substrate using DC reactive magnetron sputtering method completed the sample series. An anomalous magnetisation behaviour has been evidenced in the Verwey temperature vicinity that is shown to depend on the applied magnetic field. A magneto-electronic model explains the origin of this behaviour. The maximum in the demagnetisation at the Verwey transition has been noticed very near 0.1 T (i.e. 90 kA/m, as found out on bulk magnetite). The amount and nature of structural defects have been proven to be determinant in the magnetisation process, and the approach to saturation is well described by the M = M S ( 1 - b / B n ) relation, with n = 2 in bulk magnetite crystal and n = 0.5 in epitaxial magnetite film, even across and below the Verwey transition after paraprocess corrections. These dependences exist in the 10–300 K temperature range, excluding isotropic point (near 130 K), and demonstrate that the antiphase boundaries (APBs) are responsible for the much more progressive approach to saturation observed in thin films than in bulk samples which is consistent with previous observations. On the epitaxial film, n is found to decrease down to 0.33 at isotropic point due to an enhanced super-exchange interaction through APBs.
- Published
- 2005
24. Structure, magnetic ordering, and spin filtering efficiency of NiFe2O4(111) ultrathin films
- Author
-
Peng Wei, M.-A. Arrio, Jagadeesh S. Moodera, Ph. Sainctavit, Jean-Baptiste Moussy, Sylvia Matzen, Julio C. Cezar, Christophe Gatel, Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology (MIT), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), European Synchrotron Radiation Facility (ESRF), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Magnetoresistance ,Relaxation (NMR) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetization ,Tunnel effect ,[PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph] ,0103 physical sciences ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Thin film ,010306 general physics ,0210 nano-technology ,Quantum tunnelling ,Molecular beam epitaxy ,Spin-½ - Abstract
International audience; NiFe2O4(111) ultrathin films (3-5 nm) have been grown by oxygen-assisted molecular beam epitaxy and integrated as effective spin-filter barriers. Structural and magnetic characterizations have been performed in order to investigate the presence of defects that could limit the spin filtering efficiency. These analyses have revealed the full strain relaxation of the layers with a cationic order in agreement with the inverse spinel structure but also the presence of antiphase boundaries. A spin-polarization up to þ25% has been directly measured by the Meservey-Tedrow technique in Pt(111)/NiFe2O4(111)/c-Al2O3(111)/Al tunnel junctions. The unexpected positive sign and relatively small value of the spin-polarization are discussed, in comparison with predictions and previous indirect tunnelling magnetoresistance measurements
- Published
- 2014
25. Atomic-oxygen-assisted MBE growth of Fe3O4 (111) on α-Al2O3 (0001)
- Author
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Susana Gota, M.-J. Guittet, M. Gautier-Soyer, Jean-Baptiste Moussy, and M. Henriot
- Subjects
Reflection high-energy electron diffraction ,Low-energy electron diffraction ,Analytical chemistry ,Iron oxide ,chemistry.chemical_element ,Surfaces and Interfaces ,Condensed Matter Physics ,Oxygen ,Surfaces, Coatings and Films ,Crystallography ,chemistry.chemical_compound ,Lattice constant ,Electron diffraction ,chemistry ,X-ray photoelectron spectroscopy ,Materials Chemistry ,Molecular beam epitaxy - Abstract
The growth of Fe 3 O 4 on α-Al 2 O 3 (0 0 0 1) by atomic-oxygen-assisted molecular beam epitaxy has been studied by real time reflection high energy electron diffraction, low energy electron diffraction and X-ray photoelectron spectroscopy. The in-plane lattice parameter has been followed in situ during growth. For thickness below 1.5 nm, an iron oxide consisting on an expanded oxygen sub-lattice with an incomplete occupation of the Fe sites, is formed. This phase seems to be specific for a given thickness and independent of the growth conditions. For thickness above 1.5 nm, the long-range order of the Fe cations develops simultaneously with a decrease of the oxygen sub-lattice expansion. From this stage, Fe 3 O 4 (1 1 1) is stabilised.
- Published
- 2001
26. Percolation behaviour in intergrowth BiSrCaCuO structures grown by molecular beam epitaxy
- Author
-
C. Deville Cavellin, Michel Laguës, Jean-Baptiste Moussy, X.Z. Xu, F.C. Beuran, and J.Y. Laval
- Subjects
Diffraction ,Materials science ,Reflection high-energy electron diffraction ,Condensed matter physics ,Stacking ,Energy Engineering and Power Technology ,Condensed Matter Physics ,Epitaxy ,Electronic, Optical and Magnetic Materials ,Percolation ,Electrical and Electronic Engineering ,Thin film ,High-resolution transmission electron microscopy ,Molecular beam epitaxy - Abstract
BiSrCaCuO thin films and specially Bi-2212 compounds were grown on (100) SrTiO 3 substrates by molecular beam epitaxy (MBE). The growth mechanism was controlled in real time by monitoring the RHEED intensity. The deposition sequence of the elements was also varied in order to induce intergrowth structures at nanometer scale. The resulting high density of stacking faults is in contrast with a very low roughness (in the range of 1 nm as measured by atomic force microscopy), a strong c -axis texturation, and a full epitaxy within the ab -plane as confirmed by four circle X-ray diffraction. The local structure of the films was examined by high resolution transmission electron microscopy (HRTEM) in correlation with the superconducting properties. Both structural and transport properties seem to be deeply affected by the percolation of 2212 domains as their concentration in the film is changed.
- Published
- 2000
27. On the spin polarization at the interface probed by spin-resolved photoemission and spin-dependent tunneling
- Author
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C. De Nadaï, Karim Bouzehouane, M.-J. Guittet, Susana Gota, Jean-Baptiste Moussy, Cyrile Deranlot, M. Gautier-Soyer, N. B. Brookes, Alberto Tagliaferri, Frédéric Petroff, A. M. Bataille, Richard Mattana, and Pierre Seneor
- Subjects
Materials science ,Condensed matter physics ,Spin polarization ,Analytical chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,Epitaxy ,Spin dependent tunneling ,Electronic, Optical and Magnetic Materials ,chemistry ,Yield (chemistry) ,Electrode ,Spin (physics) ,Cobalt ,Molecular beam epitaxy - Abstract
We report on two independent measurements of the spin polarization at the Fe 3 O 4 / γ - Al 2 O 3 interface. Fe 3 O 4 / γ - Al 2 O 3 (1 1 1) bilayers have been epitaxially grown by oxygen-assisted molecular beam epitaxy onto α - Al 2 O 3 (0 0 0 1) substrates and some were covered ex situ by a cobalt electrode. Spin resolved photoemission yield to a negative spin polarization ( ≃ - 40 %) while transport measurements on Fe 3 O 4 / γ - Al 2 O 3 / Co magnetic tunnel junctions show a positive TMR, which suggest that the tunnel spin polarization at the Fe 3 O 4 / γ - Al 2 O 3 interface is positive.
- Published
- 2007
28. Transport properties of MBE grown cuprate spin ladders
- Author
-
C. Deville Cavellin, C.F. Beuran, C. Partiot, B. Eustache, Jean-Baptiste Moussy, J.Y. Laval, Michel Laguës, and X.Z. Xu
- Subjects
Superconductivity ,Diffraction ,Materials science ,Reflection high-energy electron diffraction ,Condensed matter physics ,Doping ,Analytical chemistry ,Energy Engineering and Power Technology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Electrical resistivity and conductivity ,Cuprate ,Electrical and Electronic Engineering ,Thin film ,High-resolution transmission electron microscopy - Abstract
Thin films belonging to the family of Spin Ladders (Sr,Ca) h−1 Cu h+1 O 2h are grown by MBE. The deposition is performed under atomic oxygen using real time control by the RHEED intensity. The structural parameters measured by four-circle X-ray diffraction agree with the values observed for cuprate Spin Ladders in bulk compounds from various laboratories. HRTEM images shows the double Cu rows within the CuO planes which are characteristic of ladder structures. The room temperature resistivity ranges from 1 mΩ.cm for Ca 2 Cu 4 O 6 to 1 Ω.cm for Sr 2 Cu 4 O 6 . Doping with BiO planes was tested. A superconducting transition at 40K was observed in a BiSrCaCuO compound with a composition compatible with two-leg ladders.
- Published
- 1997
29. Room temperature transport properties of new BiSrCaCuO compounds
- Author
-
Claire Partiot, Christophe Hatterer, Betty Eustache, Michel Laguës, Xiang Zhen Xu, C. F. Beuran, Jean-Baptiste Moussy, Catherine Deville Cavellin, and Vincent Mairet
- Subjects
Orders of magnitude (temperature) ,Chemistry ,Inorganic chemistry ,General Engineering ,Analytical chemistry ,chemistry.chemical_element ,Dissipation ,Epitaxy ,Copper ,Exponential function ,Electrical resistivity and conductivity ,General Earth and Planetary Sciences ,General Materials Science ,Cuprate ,Intensity (heat transfer) ,General Environmental Science - Abstract
New compounds belonging to the BiSrCaCuO cuprate family have been synthesized by sequentially imposed layer epitaxy. The Cu/Ca ratio in these compounds is typically twice the value for conventional Bi2Sr2Can−1CunO2n 4. A second characteristic of the new compounds is a Bi deficiency relative to conventional BSCCO. The room temperature electrical resistivity of these compounds reaches extremely low values, orders of magnitude below that of copper. Strongly non-linear I(V) characteristics of various forms are observed. Typical examples are described where the voltage dependence at the onset of measurable dissipation is either exponential or parabolic as a function of current intensity. Examples are also presented where I(V) exhibits an hysteretic behavior.
- Published
- 1997
30. Magnetism of CoFe$_2$O$_4$ ultrathin films on MgAl$_2$O$_4$ driven by epitaxial strain
- Author
-
Bénédicte Warot-Fonrose, Jean-Baptiste Moussy, Christophe Gatel, Sylvia Matzen, Interférométrie, In situ et Instrumentation pour la Microscopie Electronique (CEMES-I3EM), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
- Subjects
010302 applied physics ,[PHYS]Physics [physics] ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Strain (chemistry) ,Magnetism ,Relaxation (NMR) ,Relaxation process ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Epitaxy ,01 natural sciences ,Magnetic anisotropy ,Magnetization ,Geometric phase ,0103 physical sciences ,0210 nano-technology - Abstract
International audience; We report on the correlations between magnetic anisotropy and strain state in CoFe$_2$O$_4$ ultrathin films grown on MgAl$_2$O$_4$(100) and MgAl$_2$O$_4$(111) substrates. By local strain analysis using the geometric phase method, a significant in-plane compressive strain is observed for the (001) orientation while a full relaxation is detected for the (111) orientation. The relaxation process in CoFe$_2$O$_4$(111) layers induces interface dislocations and a large amount of antiphase boundaries while a pseudomorphic growth is observed for the (001) direction, decreasing significantly the density of antiphase boundaries. By comparing the magnetoelastic energy terms, the correlation between strain state and resultant magnetization is discussed.
- Published
- 2013
31. Anti-ferromagnetic coupling in hybrid magnetic tunnel junctions mediated by monomolecular layers of α-sexithiophene
- Author
-
Camille Blouzon, Denis Fichou, Ludovic Tortech, F. Ott, Jean-Baptiste Moussy, Université Pierre et Marie Curie - Paris 6 - UFR de Médecine Pierre et Marie Curie (UPMC), Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay
- Subjects
Coupling ,[PHYS]Physics [physics] ,Materials science ,Physics and Astronomy (miscellaneous) ,Spintronics ,Condensed matter physics ,Magnetometer ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Epitaxy ,01 natural sciences ,Inductive coupling ,law.invention ,Magnetization ,Nuclear magnetic resonance ,Ferromagnetism ,law ,0103 physical sciences ,Monolayer ,010306 general physics ,0210 nano-technology - Abstract
International audience; We report here on the magnetic coupling taking place between Fe3O4 and Co layers across an organic monolayer of α-sexithiophene (6T). The controlled growth of 6T ultrathin films on epitaxial Fe3O4 surfaces allows to prepare highly homogeneous insulating layers with thicknesses in the range 0.5–2.0 monolayers (ML). A combined study using vibrating sample magnetometry and polarized neutron reflectivity reveals that hybrid Fe3O4/6T/Co tunnel junctions show different magnetic couplings depending on the 6T thickness. In particular, magnetic coupling between Fe3O4 and Co layers separated by 1 ML of 6T is consistent with anti-ferromagnetic coupling, opening new perspectives for controlling magnetization in organic spintronic devices.
- Published
- 2013
32. Direct evidence of spin filtering across MnFe2O4tunnel barrier by Meservey-Tedrow experiment
- Author
-
Sylvia Matzen, Guo-Xing Miao, Jean-Baptiste Moussy, and Jagadeesh S. Moodera
- Subjects
Physics ,Superconductivity ,Spin filtering ,Condensed matter physics ,Direct evidence ,media_common.quotation_subject ,02 engineering and technology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Epitaxy ,01 natural sciences ,Asymmetry ,Electronic, Optical and Magnetic Materials ,Amplitude ,Tunnel barrier ,Condensed Matter::Superconductivity ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Spin-½ ,media_common - Abstract
A spin filtering effect has been evidenced in epitaxial MnFe${}_{2}$O${}_{4}$ tunnel barriers directly by Meservey-Tedrow experiments. The asymmetry of the Zeeman-split tunneling conductance curves of the superconducting Al spin analyzer in Pt(111)/MnFe${}_{2}$O${}_{4}$(111)/\ensuremath{\gamma}-Al${}_{2}$O${}_{3}$(111)/Al tunnel junctions revealed a positive spin-polarization (up to +9$%$), proving the potential of manganese ferrite for generation of a spin-polarized current. A negatively polarized spin filtering being expected theoretically, different mechanisms are discussed to explain both sign and amplitude of the measured spin-polarization.
- Published
- 2013
33. From epitaxial growth of ferrite thin films to spin-polarized tunnelling
- Author
-
Jean-Baptiste Moussy, Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
- Subjects
[PHYS]Physics [physics] ,Acoustics and Ultrasonics ,Spintronics ,Condensed matter physics ,Heterojunction ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Epitaxy ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Tunnel magnetoresistance ,Condensed Matter::Materials Science ,Condensed Matter::Superconductivity ,0103 physical sciences ,Ferrite (magnet) ,Condensed Matter::Strongly Correlated Electrons ,Thin film ,010306 general physics ,0210 nano-technology ,Quantum tunnelling ,Molecular beam epitaxy - Abstract
International audience; This paper presents a review of the research which is focused on ferrite thin films for spintronics. First, I will describe the potential of ferrite layers for the generation of spin-polarized currents. In the second step, the structural and chemical properties of epitaxial thin films and ferrite-based tunnel junctions will be presented. Particular attention will be given to ferrite systems grown by oxygen-assisted molecular beam epitaxy. The analysis of the structure and chemistry close to the interfaces, a key-point for understanding the spin-polarized tunnelling measurements, will be detailed. In the third part, the magnetic and magneto-transport properties of magnetite (Fe3O4) thin films as a function of structural defects such as the antiphase boundaries will be explained. The spin-polarization measurements (spin-resolved photoemission, tunnel magnetoresistance) on this oxide predicted to be half-metallic will be discussed. Fourth, the potential of magnetic tunnel barriers, such as CoFe2O4, NiFe2O4 or MnFe2O4, whose insulating behaviour and the high Curie temperatures make it exciting candidates for spin filtering at room temperature will be described. Spin-polarized tunnelling experiments, involving either Meservey–Tedrow or tunnel magnetoresistance measurements, will reveal significant spin-polarizations of the tunnelling current at low temperatures but also at room temperatures. Finally, I will mention a few perspectives with ferrite-based heterostructures.
- Published
- 2013
34. X-ray diffraction imaging of metal–oxide epitaxial tunnel junctions made by optical lithography: use of focused and unfocused X-ray beams
- Author
-
Cristian Mocuta, Antoine Barbier, Stefan Stanescu, Eric Ziegler, Jean-Baptiste Moussy, Sylvia Matzen, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and European Synchrotron Radiation Facility (ESRF)
- Subjects
Diffraction ,Nuclear and High Energy Physics ,Materials science ,02 engineering and technology ,Bending ,Curvature ,Epitaxy ,01 natural sciences ,law.invention ,Optics ,law ,raster microscopy ,0103 physical sciences ,Instrumentation ,microbeam X-ray diffraction ,010302 applied physics ,[PHYS]Physics [physics] ,X-ray imaging with diffraction contrast ,Radiation ,business.industry ,metal–oxide epitaxial tunnel junctions ,021001 nanoscience & nanotechnology ,Research Papers ,FRELON CAMERA ,X-ray crystallography ,Photolithography ,0210 nano-technology ,business ,Order of magnitude ,Beam (structure) - Abstract
Metal-oxide tunnel junctions made by optical lithography were studied by X-ray diffraction (imaging approach with diffraction contrast) to access local distortions of the crystalline planes of the constituting layers. The effect of the size (10–150 µm) and shape (disc, square and rectangle) of the junction was investigated., X-ray diffraction techniques are used in imaging mode in order to characterize micrometre-sized objects. The samples used as models are metal–oxide tunnel junctions made by optical lithography, with lateral sizes ranging from 150 µm down to 10 µm and various shapes: discs, squares and rectangles. Two approaches are described and compared, both using diffraction contrast: full-field imaging (topography) and raster imaging (scanning probe) using a micrometre-sized focused X-ray beam. It is shown that the full-field image gives access to macroscopic distortions (e.g. sample bending), while the local distortions, at the micrometre scale (e.g. tilts of the crystalline planes in the vicinity of the junction edges), can be accurately characterized only using focused X-ray beams. These local defects are dependent on the junction shape and larger by one order of magnitude than the macroscopic curvature of the sample.
- Published
- 2013
35. Artificial antiphase boundary at the interface of ferrimagnetic spinel bilayers
- Author
-
Sylvia Matzen, Ana V. Ramos, Frédéric Ott, Jean-Baptiste Moussy, and Michel Viret
- Subjects
Materials science ,Condensed matter physics ,Bilayer ,Spinel ,engineering.material ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Magnetization ,Superexchange ,Ferrimagnetism ,engineering ,Neutron ,Neutron reflectometry ,Thin film - Abstract
${\text{CoFe}}_{2}{\text{O}}_{4}/{\text{Fe}}_{3}{\text{O}}_{4}$ bilayers represent an unusual exchange-coupled system whose properties are due to the nature of the oxide-oxide superexchange interactions at the interface. In this work, we analyze the magnetization reversal behavior and magnetic interface structure using a variety of advanced techniques. Low-temperature magnetization, magnetotransport, and polarized neutron reflectivity measurements suggest that the magnetization configuration at the bilayer interface mimics that of an antiphase boundary found in spinel ferrite thin films, thus explaining the unique nature of the magnetic behavior.
- Published
- 2009
36. Influence of oxidation on the spin-filtering properties ofCoFe2O4and the resultant spin polarization
- Author
-
Jagadeesh S. Moodera, M.-J. Guittet, Ana Ramos, Jean-Baptiste Moussy, Tiffany S. Santos, and Guo-Xing Miao
- Subjects
Physics ,Spin filtering ,Spin polarization ,Condensed matter physics ,media_common.quotation_subject ,Condensed Matter Physics ,Polarization (waves) ,Epitaxy ,Asymmetry ,Electronic, Optical and Magnetic Materials ,Quasiparticle ,Density of states ,Quantum tunnelling ,media_common - Abstract
We report the direct measurement of spin polarization in epitaxial ${\text{CoFe}}_{2}{\text{O}}_{4}$ tunnel barriers using the Meservey-Tedrow technique. By observing an asymmetry in the Al quasiparticle density of states in $\text{Pt}(111)/{\text{CoFe}}_{2}{\text{O}}_{4}(111)/\ensuremath{\gamma}{\text{-Al}}_{2}{\text{O}}_{3}(111)/\text{Al}$ tunnel junctions, we prove the existence of spin filtering in our ${\text{CoFe}}_{2}{\text{O}}_{4}$ tunnel barriers. We further analyze the effect of oxidation conditions during film growth on the polarization of the tunneling current, revealing an important role played by oxygen vacancies in the spin-filter efficiency of this material.
- Published
- 2008
37. Dislocation network driven structural relaxation in hematite thin films
- Author
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Jean-Baptiste Moussy, Cristian Mocuta, M. Gautier-Soyer, Hélène Magnan, O. Bezencenet, Antoine Barbier, M.-J. Guittet, N. Jedrecy, Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), European Synchrotron Radiation Facility (ESRF), Institut des Nanosciences de Paris (INSP), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Diffraction ,Materials science ,02 engineering and technology ,Epitaxy ,01 natural sciences ,hematite ,Lattice constant ,relaxation ,dislocation network ,0103 physical sciences ,General Materials Science ,Isostructural ,Thin film ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,010306 general physics ,Mechanical Engineering ,surface X-ray diffraction ,Hematite ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Crystallography ,Mechanics of Materials ,visual_art ,visual_art.visual_art_medium ,Sapphire ,0210 nano-technology ,Molecular beam epitaxy - Abstract
Symposium on Nanoscale Tailoring of Defect Structures for Optimized Functional and Multifunctional Oxide Films held at the EMRS 2007, Strasbourg, FRANCE, 2007; International audience; Using surface X-ray diffraction, we investigated 20 nm thick alpha-Fe2O3(0 0 0 1) thin films deposited on alpha-Al2O3(0001) and Pt(111) single crystals. The films were grown in identical conditions by atomic oxygen assisted molecular beam epitaxy techniques. Both substrates offer close lattice parameter misfits. On sapphire an isostructural epitaxial relationship is observed and a 30 degrees in plane rotation of the lattice for Pt(111). The crystalline quality of the film deposited on Pt(111) is much better and contained less parasitic contributions. The improved crystalline quality of alpha-Fe2O3(0001) layers on Pt(111) is attributed to the presence of a very well ordered interfacial dislocation network which is missing when alpha-Al2O3 is used as substrate. (C) 2007 Elsevier B.V. All rights reserved.
- Published
- 2007
38. Room temperature spin filtering in epitaxial cobalt-ferrite tunnel barriers
- Author
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M.-J. Guittet, Frédéric Petroff, Christophe Gatel, Jean-Baptiste Moussy, Cyrile Deranlot, A. V. Ramos, and Richard Mattana
- Subjects
Spin filtering ,Condensed Matter - Materials Science ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Magnetoresistance ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Biasing ,Model system ,Epitaxy ,Cobalt ferrite ,Cobalt compounds ,Quantum tunnelling - Abstract
We report direct experimental evidence of room temperature spin filtering in magnetic tunnel junctions (MTJs) containing CoFe2O4 tunnel barriers via tunneling magnetoresistance (TMR) measurements. Pt(111)/CoFe2O4(111)/gamma-Al2O3(111)/Co(0001) fully epitaxial MTJs were grown in order to obtain a high quality system, capable of functioning at room temperature. Spin polarized transport measurements reveal significant TMR values of -18% at 2 K and -3% at 290 K. In addition, the TMR ratio follows a unique bias voltage dependence that has been theoretically predicted to be the signature of spin filtering in MTJs containing magnetic barriers. CoFe2O4 tunnel barriers therefore provide a model system to investigate spin filtering in a wide range of temperatures., 6 pages, 3 figures
- Published
- 2007
39. Influence of a metallic or oxide top layer in epitaxial magnetic bilayers containingCoFe2O4(111)tunnel barriers
- Author
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Ch. Gatel, Etienne Snoeck, Jean-Baptiste Moussy, M. Gautier-Soyer, M.-J. Guittet, Pascale Bayle-Guillemaud, Ana Ramos, and Bénédicte Warot-Fonrose
- Subjects
Metal ,chemistry.chemical_compound ,Materials science ,Condensed matter physics ,chemistry ,visual_art ,visual_art.visual_art_medium ,Oxide ,Condensed Matter Physics ,Epitaxy ,Layer (electronics) ,Electronic, Optical and Magnetic Materials - Published
- 2007
40. Negative spin polarization of theFe3O4∕γ−Al2O3interface measured by spin-resolved photoemission
- Author
-
Jean-Baptiste Moussy, M.-J. Guittet, Frédéric Petroff, M. Gautier-Soyer, C. De Nadaï, N. B. Brookes, Karim Bouzehouane, Susana Gota, A. M. Bataille, and Alberto Tagliaferri
- Subjects
Materials science ,Spintronics ,Condensed matter physics ,Spin polarization ,Fermi level ,Heterojunction ,Giant magnetoresistance ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,Tunnel magnetoresistance ,symbols.namesake ,Spinplasmonics ,symbols ,Condensed Matter::Strongly Correlated Electrons ,Electronic band structure - Abstract
The discovery of giant magnetoresistance in Fe/ Cr multilayers 1 has been followed by a large research effort for almost two decades aiming at developing new materials suitable for spintronics. The interest of a given material is mainly expressed by its spin polarization P =N↑ �N↓ /N↑ +N↓, N↑ N↓ standing for majority spin minority spin electron density of states at the Fermi level. This property is particularly important for magnetic tunnel junctions stacks of two magnetic electrodes separated by a thin insulating layer. 2 Indeed, the tunnel magnetoresistance TMR, corresponding to the variation of resistance between parallel and antiparallel configurations of the electrode magnetizations, is given in a simple view by the Julliere formula: 3 TMR =2 P1P2 / 1� P1P2, P1 and P2 being the spin polarizations of the two electrodes. Magnetite Fe3O4 is thus expected to be an interesting electrode material, for band structure calculations predict a half metallic behavior P = �100%, the con
- Published
- 2006
41. Experimental evidence of the spin dependence of electron reflections in magneticCoFe2O4∕Au∕Fe3O4trilayers
- Author
-
Ch. Gatel, M. Gautier-Soyer, Jean-Baptiste Moussy, G. BenAssayag, M. Pannetier, A. M. Bataille, Etienne Snoeck, and R. Serra
- Subjects
Materials science ,Spin polarization ,Condensed matter physics ,Electron ,Condensed Matter Physics ,Spin (physics) ,Electronic, Optical and Magnetic Materials - Published
- 2006
42. Electronic and crystalline structure, morphology, and magnetism of nanometricFe2O3layers deposited on Pt(111) by atomic-oxygen-assisted molecular beam epitaxy
- Author
-
Jean-Baptiste Moussy, M.-J. Guittet, Rachid Belkhou, M. Mulazzi, O. Bezencenet, M. Gautier-Soyer, Antoine Barbier, and Philippe Ohresser
- Subjects
Morphology (linguistics) ,Materials science ,Chemical engineering ,Magnetism ,Atomic oxygen ,Crystal structure ,Condensed Matter Physics ,Molecular physics ,Electronic, Optical and Magnetic Materials ,Molecular beam epitaxy - Published
- 2005
43. Thickness dependence of anomalous magnetic behavior in epitaxial Fe3O4(111) thin films: Effect of density of antiphase boundaries
- Author
-
F. Ott, F. Delille, Etienne Snoeck, Jean-Baptiste Moussy, B. Dieny, Pascale Bayle-Guillemaud, M. Gautier-Soyer, A. Bataille, P. Warin, T. D. Doan, Susana Gota, M.-J. Guittet, and Christophe Gatel
- Subjects
Magnetization ,Charge ordering ,Materials science ,Magnetic moment ,Ferromagnetism ,Condensed matter physics ,Magnetic domain ,Condensed Matter Physics ,Magnetic hysteresis ,Epitaxy ,Saturation (magnetic) ,Electronic, Optical and Magnetic Materials - Abstract
We study the magnetic behavior of ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}(111)$ thin films with thicknesses between $5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and $50\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. The films are epitaxially grown on $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}(0001)$ single crystals by atomic-oxygen-assisted molecular beam epitaxy. The ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}(111)$ thin films exhibit high structural order with sharp interfaces and low roughness and exhibit a Verwey transition for thicknesses above $8\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. However, the samples have magnetic properties that deviate from the bulk ones. The magnetic moment varies between $2.4{\ensuremath{\mu}}_{B}$ for $5\text{\ensuremath{-}}\mathrm{nm}$-thick film and $3.2{\ensuremath{\mu}}_{B}$ for $50\text{\ensuremath{-}}\mathrm{nm}$-thick film in a field of $1.2\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, which is lower than that of bulk samples ($4.1{\ensuremath{\mu}}_{B}∕{\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ formula). Still the magnetic saturation is never reached, even in fields as large as $2\phantom{\rule{0.3em}{0ex}}T$. The thinner the film, the slower the approach to saturation. Structural analysis, performed using high-resolution transmission electron microscopy, reveals the presence of antiphase boundaries (APB's), the density of which decreases when the thickness increases. Using a model of ferromagnetic domains separated by antiferromagnetically sharp interfaces, we show that the slow approach to saturation observed in the films as a function of thickness is driven by the APB density.
- Published
- 2004
44. Nanomagnetism of cobalt ferrite-based spin filters probed by spin-polarized tunneling
- Author
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Frédéric Petroff, Jean-Baptiste Moussy, Sylvia Matzen, Richard Mattana, Cyrile Deranlot, and Karim Bouzehouane
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Magnetic domain ,Condensed matter physics ,Condensed Matter::Other ,Magnetism ,chemistry.chemical_element ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter::Materials Science ,Magnetic anisotropy ,Tunnel magnetoresistance ,chemistry ,Condensed Matter::Superconductivity ,Ferrite (magnet) ,Cobalt ,Nanoscopic scale ,Quantum tunnelling - Abstract
The magnetism of ferrite ultrathin films has been probed at nanoscale by spin-polarized tunneling transport in CoFe2O4-based room-temperature spin filters. By significantly reducing the Pt/CoFe2O4/Al2O3/Co junctions’ size (cross sections ∼5 nm) in comparison with usual microjunctions, transport through a ferrite single magnetic domain has been achieved. Our tunnel magnetoresistance measurements at the nanoscale have revealed very well defined resistance states and the generation of the highest spin filtering efficiency (−8%) at room temperature. A uniaxial magnetic anisotropy has been evidenced in CoFe2O4, showing that these magnetotransport measurements offer a unique probe of a single magnetic domain in ferrite ultrathin films.
- Published
- 2012
45. Restoration of bulk magnetic properties by strain engineering in epitaxial CoFe2O4 (001) ultrathin films
- Author
-
Christophe Gatel, Richard Mattana, Frédéric Petroff, Ph. Sainctavit, Sylvia Matzen, Julio C. Cezar, Jean-Baptiste Moussy, Antoine Barbier, Bénédicte Warot-Fonrose, and M.-A. Arrio
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Magnetic circular dichroism ,Spinel ,engineering.material ,equipment and supplies ,Magnetic anisotropy ,Strain engineering ,Nuclear magnetic resonance ,Ferromagnetism ,Transmission electron microscopy ,engineering ,Composite material ,Magnetic force microscope ,Anisotropy ,human activities - Abstract
We report on the significantly enhanced in-plane magnetic properties of CoFe2O4 (001) ultrathin layers (5 nm) grown on MgAl2O4 (001) in comparison to films deposited on MgO (001). The predicted inverse spinel structure is confirmed by x-ray magnetic circular dichroism measurements and transmission electronic microscopy studies reveal a significant in-plane compressive strain, responsible for the strong film anisotropy. These results show that strain engineering can be used to tailor the magnetic properties of oxide ultrathin films. A large compressive strain restores bulk magnetic properties for CoFe2O4 films at tunnel barrier thicknesses.
- Published
- 2011
46. Organic-inorganic magnetic tunnel heterojunctions based on dithiapyrannylidene ultrathin films grown on Fe3O4(111)
- Author
-
Jean-Baptiste Moussy, Denis Fichou, Sylvia Matzen, Ludovic Tortech, and Stéphane Berny
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Magnetometer ,Analytical chemistry ,Heterojunction ,Epitaxy ,Thermal conduction ,law.invention ,Planar ,law ,Electrode ,Optoelectronics ,business ,Quantum tunnelling ,Decoupling (electronics) - Abstract
We report on the morphology, transport, and magnetic properties of ultrathin films of 4,4′-bis(diphenyl-2,6-thiapyrannylidene) (DITPY-Ph4), a planar quinoid organic compound with potential applications in electronics. Atomic force microscopy (AFM) shows that highly homogeneous and continuous DITPY-Ph4 ultrathin films with thicknesses as low as 2 nm can be grown on epitaxial Fe3O4(111). Current-sensing AFM performed on ultrathin layers evidences an insulating behavior with a nonresonant tunneling conduction regime. Vibrating sample magnetometry achieved on Fe3O4/DITPY-Ph4/Co organic-inorganic heterojunctions reveals the decoupling between the two magnetic electrodes and demonstrates that DITPY-Ph4 can be used to build magnetic tunnel junctions.
- Published
- 2010
47. Growth and magnetic behavior in hybrid organic–inorganic Ferrite/Alq3/Co heterostructures
- Author
-
Frédéric Ott, Marie-Joseph Guittet, Jean-Baptiste Moussy, Florentin Rengnez, Denis Fichou, Sylvia Matzen, and Ludovic Tortech
- Subjects
Spintronics ,business.industry ,Chemistry ,Mineralogy ,Heterojunction ,General Chemistry ,Surface finish ,Organic inorganic ,Electrode ,Materials Chemistry ,Optoelectronics ,Ferrite (magnet) ,Nanometre ,business ,Decoupling (electronics) - Abstract
We report the growth and magnetic properties of AFe2O4/Alq3/Co heterostructures (AFe, Co) containing a continuous Alq3 thin layer with a low roughness, down to a few nanometers, and we demonstrate the magnetic decoupling between AFe2O4 and Co electrodes showing the interest of these systems for spintronics devices.
- Published
- 2009
48. Effect of optical lithography patterning on the crystalline structure of tunnel junctions
- Author
-
Stefan Stanescu, Antoine Barbier, Jean-Baptiste Moussy, Cyrile Deranlot, A. V. Ramos, Frédéric Petroff, M.-J. Guittet, Cristian Mocuta, and Richard Mattana
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Optical distortion ,Magnetic tunnelling ,Crystal structure ,Limiting ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,eye diseases ,law.invention ,Condensed Matter::Materials Science ,Amplitude ,Tilt (optics) ,Optics ,law ,Condensed Matter::Superconductivity ,Distortion ,Optoelectronics ,sense organs ,Photolithography ,business - Abstract
The crystalline structure of metal-oxide-based magnetic tunnel junctions patterned by optical lithography was resolved locally using a microfocused x-ray spot. We evidence several micron-sized lithography-induced distortion effects on the crystalline structure of the layers near the edges of the junction. The distortions translate into tilts (up to 1°) of the crystalline planes in the vicinity of the edges and propagate toward the center of the junction. They are attributed to the release of the elastic strain in the layers during the lithographical process. For the smallest junctions, size effects limiting the amplitude of the tilt are also evidenced.
- Published
- 2007
49. Magnetotransport properties of Fe3O4 epitaxial thin films: Thickness effects driven by antiphase boundaries
- Author
-
A. V. Ramos, Michel Viret, Pascale Bayle-Guillemaud, Etienne Snoeck, A. M. Bataille, Jean-Baptiste Moussy, M.-J. Guittet, Christophe Gatel, and M. Gautier-Soyer
- Subjects
Condensed Matter::Materials Science ,Materials science ,Condensed matter physics ,Magnetoresistance ,Ferromagnetism ,Electrical resistivity and conductivity ,Condensed Matter::Superconductivity ,Epitaxial thin film ,General Physics and Astronomy ,Large range ,Epitaxy ,Molecular beam epitaxy ,Magnetic field - Abstract
We present an in-depth study of the magnetotransport properties of epitaxial Fe3O4 films as a function of film thickness. The films, grown on α-Al2O3(0001) single crystals by atomic-oxygen assisted molecular beam epitaxy, exhibit high structural order and abrupt interfaces. These films contain antiphase boundaries (APBs), the density of which is strongly dependent on film thickness. A series of resistivity and magnetoresistance measurements demonstrate a systematic evolution of these properties with decreasing film thickness, revealing the impact of APBs on the transport properties in the films. We present a model based on the spin-polarized transport across an antiferromagnetically coupled APB in order to successfully reproduce our experimental data over a large range of applied magnetic fields. The comparison of this model with experimental results further clarifies the mechanism of the anomalous magnetotransport behavior in Fe3O4.
- Published
- 2006
50. Crystalline γ-Al2O3 barrier for magnetite-based magnetic tunnel junctions
- Author
-
F. Paumier, P. Warin, Pierre Seneor, Pascale Bayle-Guillemaud, M.-J. Guittet, Jean-Baptiste Moussy, Frédéric Petroff, A. M. Bataille, M. Gautier-Soyer, Susana Gota, and Karim Bouzehouane
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Analytical chemistry ,Epitaxy ,chemistry.chemical_compound ,Charge ordering ,Magnetization ,chemistry ,X-ray photoelectron spectroscopy ,Transmission electron microscopy ,Sapphire ,Optoelectronics ,business ,Layer (electronics) ,Magnetite - Abstract
We report on the elaboration and physical properties of fully epitaxial Fe3O4∕Al2O3 bilayers to be included in magnetic tunnel junctions. Uncovered Fe3O4(111) single layers and bilayers were epitaxially grown onto sapphire (0001) substrates. Appropriate growth conditions lead to a stoichiometric Fe3O4 layer both at the Fe3O4∕Al2O3 interface and on the whole thickness, as checked by in situ x-ray photoelectron spectroscopy and by the observation of the Verwey transition, respectively. Transmission electron microscopy demonstrates the epitaxial growth of a γ-Al2O3 layer on top of Fe3O4(111), which insulating properties have been monitored by conductive tip atomic force microscopy.
- Published
- 2005
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