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15 results on '"Michal Staňo"'

1. Observing high-k magnons with Mie-resonance-enhanced Brillouin light scattering

Author

Ondřej Wojewoda, Filip Ligmajer, Martin Hrtoň, Jan Klíma, Meena Dhankhar, Kristýna Davídková, Michal Staňo, Jakub Holobrádek, Jakub Krčma, Jakub Zlámal, Tomáš Šikola, and Michal Urbánek

Subjects
Astrophysics, QB460-466, Physics, QC1-999
Abstract

Abstract Local probing of dynamic excitations such as magnons and phonons in materials and nanostructures can bring new insights into their properties and functionalities. For example, in magnonics, many concepts and devices recently demonstrated at the macro- and microscale now need to be realized at the nanoscale. Brillouin light scattering (BLS) spectroscopy and microscopy has become a standard technique for spin wave characterization, and enabled many pioneering magnonic experiments. However, the conventional BLS cannot detect nanoscale waves due to its fundamental limit in maximum detectable quasiparticle momentum. Here we show that optically induced Mie resonances in nanoparticles can be used to extend the range of accessible quasiparticle’s wavevectors beyond the BLS fundamental limit. These experiments involve the measurement of thermally excited as well as coherently excited high momentum magnons. Our findings demonstrate the capability of Mie-enhanced BLS and significantly extend the usability of BLS microscopy for magnonic and phononic research.

Published
2023
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2. Flux-closure domains in high aspect ratio electroless-deposited CoNiB nanotubes

Author

Michal Staňo, Sandra Schaefer, Alexis Wartelle, Maxime Rioult, Rachid Belkhou, Alessandro Sala, Tevfik Onur Menteş, Andrea Locatelli, Laurent Cagnon, Beatrix Trapp, Sebastian Bochmann, Sylvain Martin, Eric Gautier, Jean-Christophe Toussaint, Wolfgang Ensinger, Olivier Fruchart

Subjects
Physics, QC1-999
Abstract

We report the imaging of magnetic domains in ferromagnetic CoNiB nanotubes with very long aspect ratio, fabricated by electroless plating. While axial magnetization is expected for long tubes made of soft magnetic materials, we evidence series of azimuthal domains. We tentatively explain these by the interplay of anisotropic strain and/or grain size, with magneto-elasticity and/or anisotropic interfacial magnetic anisotropy. This material could be interesting for dense data storage, as well as curvature-induced magnetic phenomena such as the non-reciprocity of spin-wave propagation.

Published
2018
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5. Preserving Metamagnetism in Self-Assembled FeRh Nanomagnets

Author

Lucie Motyčková, Jon Ander Arregi, Michal Staňo, Stanislav Průša, Klára Částková, and Vojtěch Uhlíř

Subjects
Condensed Matter - Materials Science, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Materials Science
Abstract

We present self-assembly routes of metamagnetic FeRh nanoisland arrays using sputter deposition processing. Controlling the growth parameters and epitaxy allows tuning the size and shape of the FeRh nanoislands. While the phase transition between antiferromagnetic and ferromagnetic order is largely suppressed in nanoislands formed on oxide substrates via thermodynamic nucleation, we find that metamagnetism is largely preserved in nanomagnet arrays formed through solid-state dewetting. This behavior is strongly dependent on the resulting crystal faceting of the nanoislands, which is characteristic of each assembly route. Comparing the calculated surface energies for each magnetic phase of the nanoislands reveals that metamagnetism can be suppressed or allowed by specific geometrical configurations of the facets. Furthermore, we find that the spatial confinement leads to very pronounced supercooling and the absence of phase separation in the nanoislands. Finally, the supported nanomagnets are chemically etched away from the substrates to inspect the phase transition properties of self-standing nanoparticles. We demonstrate that solid-state dewetting is a feasible and scalable way to obtain supported and free-standing FeRh nanomagnets with preserved metamagnetism., Comment: 28 pages, 7 figures, 1 table

Published
2022
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6. Theoretical study of current-induced domain wall motion in magnetic nanotubes with azimuthal domains

Author

Arnaud De Riz, Jérôme Hurst, Michal Staňo, Olivier Fruchart, Jean-Christophe Toussaint, Daria Gusakova, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Central European Institute of Technology [Brno] (CEITEC MU), Brno University of Technology [Brno] (BUT), Micro et NanoMagnétisme (MNM), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), ANR-17-CE24-0017,MATEMAC-3D,Manipulation de textures magnétiques par courant – modélisation 3D par éléments finis(2017), Micro et NanoMagnétisme (NEEL - MNM), and ANR-18-CE92-0045,C3DS,Chimie pour une spintronique 3D(2018)

Subjects
Physics, Magnetic domain, Field (physics), Condensed matter physics, Exchange interaction, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Magnetic anisotropy, Magnetization, Domain wall (magnetism), [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Electric current, 010306 general physics, 0210 nano-technology, Anisotropy
Abstract

We report a theoretical overview of the magnetic domain wall behavior under an electric current in infinitely long nanotubes with azimuthal magnetization, combining the one-dimensional analytic model and micromagnetic simulations. We highlight effects that, besides spin-transfer torques already largely understood in flat strips, arise specifically in the tubular geometry: the \OE{}rsted field and curvature-induced magnetic anisotropy resulting both from the exchange interaction and material growth. Depending on both the geometry of the tube and the strength of the azimuthal anisotropy, Bloch or N\'eel walls arise at rest, resulting in two regimes of motion largely dominated by either spin-transfer torques or the \OE{}rsted field. We determine the Walker breakdown current in all cases, and highlight the most suitable parameters to achieve high domain wall speed.

Published
2021
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7. Transmission XMCD-PEEM imaging of an engineered vertical FEBID cobalt nanowire with a domain wall

Author

Alexis Wartelle, Javier Pablo-Navarro, Michal Staňo, Sebastian Bochmann, Sébastien Pairis, R. Belkhou, Maxime Rioult, José María de Teresa, C. Thirion, Olivier Fruchart, César Magén, Ministerio de Economía y Competitividad (España), Gobierno de Aragón, European Commission, Agence Nationale de la Recherche (France), Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratorio de microscopias avanzadas (LMA), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Optique et microscopies (POM), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Instituto de Ciencia de Materiales de Aragón [Saragoza, España] (ICMA-CSIC), Fundación ARAID, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Spanish Ministry of Economy and Competitivity through projects No. MAT2014-51982C2-1-R, MAT2014-51982C2-2-R and MAT2015-69725-REDT, including FEDER fundsThe Aragon Regional Government (Construyendo Europa desde Aragón) through project E26, with FEDER funding.The Ayuda para Contratos Predoctorales para la Formación de Doctores, Convocatoria Res. 05/06/15 (BOE 12/06/15) of the Secretaría de Estado de Investigación, Desarrollo e Innovación in the Subprograma Estatal de Formación of the Spanish Ministry of Economy and Competitiveness (MINECO) with the participation of the European Social Fund, ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), Micro et NanoMagnétisme (NEEL - MNM), Croissance Cristalline et MicroAnalyse (NEEL - C2MA), and Fundación Agencia Aragonesa para la Investigación y el Desarrollo (ARAID)

Subjects
Nanostructure, Nanowire, chemistry.chemical_element, FOS: Physical sciences, Bioengineering, 02 engineering and technology, Substrate (electronics), 01 natural sciences, Condensed Matter::Materials Science, XMCD-PEEM, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Perpendicular, General Materials Science, Electrical and Electronic Engineering, 010302 applied physics, Physics, Condensed Matter - Materials Science, Ferromagnetic nanowires, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Magnetic circular dichroism, Mechanical Engineering, Three-dimensional nanostructures, Materials Science (cond-mat.mtrl-sci), General Chemistry, 021001 nanoscience & nanotechnology, 3. Good health, Photoemission electron microscopy, chemistry, Mechanics of Materials, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, 0210 nano-technology, business, Cobalt, FEBID, Beam (structure)
Abstract

Using focused electron-beam-induced deposition, we fabricate a vertical, platinum-coated cobalt nanowire with a controlled three-dimensional structure. The latter is engineered to feature bends along the height: these are used as pinning sites for domain walls, which are obtained at remanence after saturation of the nanostructure in a horizontally applied magnetic field. The presence of domain walls is investigated using x-ray magnetic circular dichroism (XMCD) coupled to photoemission electron microscopy (PEEM). The vertical geometry of our sample combined with the low incidence of the x-ray beam produce an extended wire shadow which we use to recover the wire's magnetic configuration. In this transmission configuration, the whole sample volume is probed, thus circumventing the limitation of PEEM to surfaces. This article reports on the first study of magnetic nanostructures standing perpendicular to the substrate with XMCD-PEEM. The use of this technique in shadow mode enabled us to confirm the presence of a domain wall without direct imaging of the nanowire., This work was supported by Spanish Ministry of Economy and Competitivity through projects No. MAT2014-51982C2-1-R, MAT2014-51982C2-2-R and MAT2015-69725-REDT, including FEDER funds, and by the Aragon Regional Government (Construyendo Europa desde Aragón) through project E26, with FEDER funding. Javier Pablo-Navarro grant is funded by the Ayuda para Contratos Predoctorales para la Formación de Doctores, Convocatoria Res. 05/06/15 (BOE 12/06/15) of the Secretaría de Estado de Investigación, Desarrollo e Innovación in the Subprograma Estatal de Formación of the Spanish Ministry of Economy and Competitiveness (MINECO) with the participation of the European Social Fund. Michal Staňo acknowledges grant from the Laboratoire d’excellence LANEF in Grenoble (ANR10-LABX-51-01).

Published
2019
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8. Flux-closure domains in high aspect ratio electroless-deposited CoNiB nanotubes

Author

Eric Gautier, Laurent Cagnon, Michal Staňo, B. Trapp, Maxime Rioult, Rachid Belkhou, Wolfgang Ensinger, Jean-Christophe Toussaint, Sandra Schaefer, Alessandro Sala, Tevfik Onur Menteş, Sebastian Bochmann, Andrea Locatelli, Sylvain Martin, Olivier Fruchart, Alexis Wartelle, Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Department of Materials Science, Darmstadt University of Technology [Darmstadt], Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Elettra Sincrotrone Trieste, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), LOEWE project RESPONSE of the Hessen State Ministry of Higher Education, Research and the Arts (HMWK), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), and Micro et NanoMagnétisme (NEEL - MNM)

Subjects
Condensed Matter - Materials Science, Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Magnetic domain, Condensed matter physics, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Flux, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Grain size, lcsh:QC1-999, Magnetic anisotropy, Magnetization, Magnetic Phenomena, Ferromagnetism, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 010306 general physics, 0210 nano-technology, Anisotropy, lcsh:Physics
Abstract

We report the imaging of magnetic domains in ferromagnetic CoNiB nanotubes with very long aspect ratio, fabricated by electroless plating. While axial magnetization is expected for long tubes made of soft magnetic materials, we evidence series of azimuthal domains. We tentatively explain these by the interplay of anisotropic strain and/or grain size, with magneto-elasticity and/or anisotropic interfacial magnetic anisotropy. This material could be interesting for dense data storage, as well as curvature-induced magnetic phenomena such as the non-reciprocity of spin-wave propagation., Comment: Focus only on azimuthal domains, information on domain walls (part of v1) removed - title, abstract and discussion changed accordingly, tubular racetracks scheme removed; new references, figures. Submission to SciPost (reformatted, new abstract, DOI added to references). Enhanced discussion of anisotropy, disagreement of synchrotron data and magnetometry rectified, new MOKE data added

Published
2018
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9. Bloch-point-mediated topological transformations of magnetic domain walls in cylindrical nanowires

Author

Andrea Locatelli, Michael Foerster, Lucia Aballe, B. Trapp, Olivier Fruchart, Jean-Christophe Toussaint, Julien Bachmann, Alexis Wartelle, T. O. Menteş, C. Thirion, Laurent Cagnon, Michal Staňo, Alessandro Sala, Sebastian Bochmann, Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Saint-Petersburg State University, ALBA Synchrotron light source [Barcelone], Elettra Sincrotrone Trieste, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), European Project: 309589,EC:FP7:NMP,FP7-NMP-2012-SMALL-6,M3D(2012), Micro et NanoMagnétisme (NEEL - MNM), and Saint Petersburg State University (SPBU)

Subjects
Field (physics), Magnetic domain, Nucleation, Nanowire, FOS: Physical sciences, 02 engineering and technology, STRIPS, Topology, 01 natural sciences, law.invention, Condensed Matter::Materials Science, Singularity, law, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Bloch point, 010306 general physics, Topology (chemistry), Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Materials Science (cond-mat.mtrl-sci), Magnetic domain wall, 021001 nanoscience & nanotechnology, Transformation (function), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology
Abstract

International audience; Cylindrical nanowires made of soft magnetic materials, in contrast to thin strips, may host domain walls of two distinct topologies. Unexpectedly, we evidence experimentally the dynamic transformation of topology upon wall motion above a field threshold. Micromagnetic simulations highlight the underlying precessional dynamics for one way of the transformation, involving the nucleation of a Bloch-point singularity, however, fail to reproduce the reverse process. This rare discrepancy between micromagnetic simulations and experiments raises fascinating questions in material and computer science.

Published
2018
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10. Probing domain walls in cylindrical magnetic nanowires with electron holography

Author

Aurélien Masseboeuf, Jean-Christophe Toussaint, Olivier Fruchart, Ségolène Jamet, Julien Bachmann, Christophe Gatel, Sebastian Bochmann, Michal Staňo, Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Interférométrie, In situ et Instrumentation pour la Microscopie Electronique (CEMES-I3EM), 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)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), European Project: 309589,EC:FP7:NMP,FP7-NMP-2012-SMALL-6,M3D(2012), Micro et NanoMagnétisme (NEEL - MNM), 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), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
History, Condensed Matter - Materials Science, Materials science, Magnetic domain, Condensed matter physics, Nanowire, Holography, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, Electron, 021001 nanoscience & nanotechnology, Electrostatics, 01 natural sciences, Electron holography, Computer Science Applications, Education, law.invention, Transverse plane, Domain wall (magnetism), law, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 010306 general physics, 0210 nano-technology
Abstract

We probe magnetic domain walls in cylindrical soft magnetic nanowires using electron holography. We detail the modelling of expected contrast for both transverse and Bloch point domain walls and provide comparison with experimental observations performed on NiCo nanowires, involving also both magnetic and electrostatic contribution to the electron holography map. This allows the fast determination of the domain wall type without the need for uneasy and time-consuming experimental removal of the electrostatic contribution. Finally, we describe and implement a new efficient algorithm for calculating the magnetic contrast., Comment: 3 pages, 2 figures

Published
2017
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11. Nucleation, imaging and motion of magnetic domain walls in cylindrical nanowires

Author

Laurent Cagnon, S. Le Denmat, Michal Staňo, Jean-Christophe Toussaint, S. Da Col, Olivier Fruchart, B. Trapp, S Jamet, Micro et NanoMagnétisme (NEEL - MNM), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Optique & Microscopies (NEEL - POM), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), European Project: 309589,EC:FP7:NMP,FP7-NMP-2012-SMALL-6,M3D(2012), Micro et NanoMagnétisme (MNM ), and Optique et microscopies (POM)

Subjects
010302 applied physics, Permalloy, Condensed Matter - Materials Science, Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Magnetic domain, Nucleation, Nanowire, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Magnetic field, Magnetization, Condensed Matter::Materials Science, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Magnetic force microscope, 0210 nano-technology, Quasistatic process
Abstract

International audience; We report several procedures for the robust nucleation of magnetic domain walls in cylindrical permalloy nanowires. Specific features of the magnetic force microscopy (MFM) contrast of such wires are discussed, to avoid the misinterpretation of the magnetization states. The domain walls moved under quasistatic magnetic fields in the range 0.1–10 mT, as evidenced by MFM at remanence at different stages of their motion.

Published
2016
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12. Preparation and physical properties of soft magnetic nickel-cobalt three-segmented nanowires

Author

Julien Bachmann, Dirk Döhler, Sebastian Bochmann, B. Trapp, Olivier Fruchart, and Michal Staňo

Subjects
Materials science, Anodizing, Nanowire, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Magnetization, Atomic layer deposition, Dipole, Nickel, chemistry, Composite material, 0210 nano-technology, Electroplating, Porosity
Abstract

We review a method to produce cylindrical magnetic nanowires displaying several segments, with a large versatility in terms of segment diameter and length. It is based on electroplating in alumina templates, the latter being prepared by several steps of anodization, wet etching, and atomic layer deposition to produce, widen, or shrink pores, respectively. We propose an analytical model to analyze the in-plane and out-of-plane magnetization loops of dense assemblies of multisegmented wires. The model considers inter-wires dipolar fields and end-domain curling and predicts the switching field of individual wires with no adjustable parameter. Its ingredients are crucial to extract reliable parameters from the fitting of loops, such as magnetization or the porosity of the array.

Published
2018
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13. Design and Optimization of a High-Speed Switched Reluctance Motor

Author

Stefan Kocan, Pavol Rafajdus, Ronald Bastovansky, Richard Lenhard, and Michal Stano

Subjects
high-speed motor, switched reluctance motor, finite element method, electromagnetic analysis, mechanical analysis, thermal analysis, Technology
Abstract

Currently, one of the most used motor types for high-speed applications is the permanent-magnet synchronous motor. However, this type of machine has high costs and rare earth elements are needed for its production. For these reasons, permanent-magnet-free alternatives are being sought. An overview of high-speed electrical machines has shown that the switched reluctance motor is a possible alternative. This paper deals with design and optimization of this motor, which should achieve the same output power as the existing high-speed permanent-magnet synchronous motor while maintaining the same motor volume. The paper presents the initial design of the motor and the procedure for analyses performed using analytical and finite element methods. During the electromagnetic analysis, the influence of motor geometric parameters on parameters such as: maximum current, average torque, torque ripple, output power, and losses was analyzed. The analysis of windage losses was performed by analytical calculation. Based on the results, it was necessary to create a cylindrical rotor shape. The rotor modification method was chosen based on mechanical analysis. Using thermal analysis, the design was modified to meet thermal limits. The result of the work was a design that met all requirements and limits.

Published
2021
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14. Sensorless Speed Control of Brushed DC Motor Based at New Current Ripple Component Signal Processing

Author

Michal Vidlak, Lukas Gorel, Pavol Makys, and Michal Stano

Subjects
sensorless speed control, brushed DC motor, commutation, current ripple, discrete bandpass filter, Technology
Abstract

Signal processing of the brushed DC motor current was developed in this paper to obtain information about a rotor speed from a measured motor current. The brushed DC motor current contains a signal with a frequency proportional to the rotor speed. This signal is the outcome of a commutation process occurring in the brushed DC motor, and it is called a ripple component. Since the number of ripples in the measured motor current per one rotation is constant, the rotor speed can be estimated. A discrete bandpass filter with a floating bandwidth was developed as the main part of signal processing. This new interpretation of the bandpass filter was used to extract a frequency of the ripple component from the measured motor current. This frequency was used to acquire information about the estimated rotor speed. The estimated speed was set as a feedback value to a cascade control structure to provide sensorless speed control. The advantages and limitations of this approach are presented in this paper. Based on simulations and experimental results, it was confirmed that the proposed sensorless speed control is robust, accurate, and works precisely in a wide range of speeds.

Published
2021
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15. High-sensitivity mapping of magnetic induction fields with nanometer-scale resolution: comparison of off-axis electron holography and pixelated differential phase contrast

Author

Olivier Fruchart, Jean-Luc Rouvière, Victor Boureau, Michal Staňo, and David Cooper, Jean-Christophe Toussaint, 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), CIME EPFL, Ecole Polytechnique Fédérale de Lausanne (EPFL), Micro et NanoMagnétisme (MNM), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Central European Institute of Technology [Brno] (CEITEC MU), Brno University of Technology [Brno] (BUT), Laboratoire d'Etude des Matériaux par Microscopie Avancée (LEMMA ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Nanocharacterisation platform based at Minatec (PFNC), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), European Project: 306535,EC:FP7:ERC,ERC-2012-StG_20111012,HOLOVIEW(2012), 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 Micro et NanoMagnétisme (NEEL - MNM)

Subjects
Diffraction, Materials science, electron holography, Acoustics and Ultrasonics, Holography, FOS: Physical sciences, Applied Physics (physics.app-ph), 02 engineering and technology, 01 natural sciences, Electron holography, law.invention, Optics, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Scanning transmission electron microscopy, stem, Image resolution, 010302 applied physics, Condensed Matter - Mesoscale and Nanoscale Physics, detector, business.industry, Resolution (electron density), Detector, pixelated stem, Physics - Applied Physics, 021001 nanoscience & nanotechnology, Condensed Matter Physics, equipment and supplies, pixelated dpc, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, electric field, lorentz microscopy, Transmission electron microscopy, magnetic induction, specimens, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 4d-stem, microscopy, precision, 0210 nano-technology, business
Abstract

We compare two transmission electron microscopy (TEM) based techniques that can provide highly spatially resolved quantitative measurements of magnetic induction fields at high sensitivity. To this end, the magnetic induction of a ferromagnetic NiFe nanowire has been measured and compared to micromagnetic modeling. State-of-the-art off-axis electron holography has been performed using the averaging of large series of holograms to improve the sensitivity of the measurements. These results are then compared to those obtained from pixelated differential phase contrast, a technique that belongs to pixelated (or 4D) scanning transmission electron microscopy (STEM) experiments. This emerging technique uses a pixelated detector to image the local diffraction patterns as the beam is scanned over the sample. For each diffraction pattern, the deflection of the beam is measured and converted into magnetic induction, while scanning the beam allows a map to be generated. Aberration corrected Lorentz (field-free) configurations of the TEM and STEM were used for an improved spatial resolution. We show that the pixelated STEM approach, even when performed using an old generation of charge-coupled device camera, provides better sensitivity at the expense of spatial resolution. A more general comparison of the two quantitative techniques is given.

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