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10 MeV proton-irradiation effects on a YBCO-based test structure were analyzed by measuring its current-voltage (IV) characteristics for different cumulated fluences. For fluences of up to $\sim$80$\cdot$10$^9$~p/cm$^2$ no changes in the electrical behavior of the device were observed, while for a fluence of $\sim$~300$\cdot$10$^9~$ p/cm$^2$ it becomes less conducting. A detailed analysis of the room temperature IV characteristics based on the $\gamma$ power exponent parameter [$\gamma=dLn(I)/dLn(V)$] allowed us to reveal the main conduction mechanisms as well as to establish the equivalent circuit model of the device. The changes produced in the electrical behavior, in accordance with Monte Carlo TRIM simulations, suggest that the main effect induced by protons is the displacement of oxygen atoms within the YBCO lattice, particularly from oxygen-rich to oxygen-poor areas, where they become trapped., Comment: 22 pages, 7 figures, corresponding author: acha@df.uba.ar

Silicon photomultipliers (SiPMs) are novel optoelectronic devices of solid-state technology. They have several advantages with respect to the traditional photomultiplier tubes, such as a superior Photon Detection Efficiency and time resolution. They are compact, mechanically robust, insensitive to magnetic fields and require a relatively low bias voltage, which are attractive characteristics for space-borne applications. In this work, we present the design of an Analog Front-End (AFE) Electronics for SiPMs, optimized for ultra low-light space-borne applications. The system is composed by a transimpedance amplifier and a high speed comparator with differential LVDS output for data transmission. Design considerations are discussed and the fabrication of a prototype is presented, along with analog and digital characterization measurements performed on it.

La0·8Ba0·2MnO3, Ba0·25Sr0·75TiO3 and BaTiO3 superlattices were grown to study the influence of structural disorder on the physical properties of multiferroic multilayers. Controlling the lattice mismatch of the superlattices allowed growing structures with different growth mechanisms. The manganite layers in the samples were used as “sensor layers”, that respond to the structural changes in the superlattices, induced by changing the thickness and nature of the ferroelectric layers. Stress has a weak influence on the magnetic properties of these systems. Transport properties are characterized by a high temperature thermally activated regime and a low temperature variable hopping one. The strain and structural disorder in the samples increases the localization energy of the current carriers for both regimes. Important interface effects can be achieved controlling the strain and disorder in the interfaces, allowing tuning the metal-insulator transition temperature. These results help to further understand the role of interface effects in the development of manganite based ferromagnetic/ferroelectric multilayered systems.

In this work we present a Conducting Atomic Force Microscopy (CAFM) study of TiO2 thin films that display bipolar resistive switching behavior. Samples were synthesized by reactive sputtering after a lithography process to obtain the bottom Au electrodes on a SiO2/Si substrate. Pt and Pt-Ir coated tips were used for CAFM measurements. We compare these results with I-V characteristics of the same device with Al top electrodes in a crossbar pattern. We demonstrate the existence of two stable resistive states and the bipolar nature of the switching through current-voltage CAFM measurements, discussing the possible transport and switching mechanisms., The authors acknowledge financial support from PICT 2013-0778 “MeMOSat”, UNSAM-ECyT FP-001 and EULANET CERMAT project (PIRSES-GA-2011-295197).

Artificially engineered superlattices were designed and fabricated to induce different growth mechanisms and structural characteristics. DC sputtering was used to grow ferromagnetic (La0.8Ba0.2MnO3)/ferroelectric (Ba0.25Sr0.75TiO3 or BaTiO3) superlattices. We systematically modified the thickness of the ferromagnetic layer to analyze dimensional and structural disorder effects on the superlattices with different structural characteristics. The crystalline structure was characterized by X-ray diffraction and transmission electron microscopy. The magnetic and electronic properties were investigated by SQUID magnetometry and resistance measurements. The results show that both strain and structural disorder can significantly affect the physical properties of the systems. Ba0.25Sr0.75TiO3 based superlattices with a low thickness of the ferromagnetic layers (4 nm) present compressive strain that decreases the ferromagnetic transition temperature from 250 K corresponding to the unstressed samples to 230 K. In these samples, the localization energy of the charge carrier through the electron-phonon interaction decreases at low temperatures (∼100 meV). Ba0.25Sr0.75TiO3 based superlattices with thicknesses of the ferromagnetic layers higher than 12 nm present tensile strain that reduces the charge carrier localization energy at low temperatures (∼1 meV), increasing the ferromagnetic transition temperature (Tc∼265 K). Structural defects in BaTiO3 based superlattices have a stronger influence on the magnetic properties than on the transport properties. Nevertheless, disorder blocks the ferromagnetic transition for highly disordered samples (thickness of the ferromagnetic layer

We report on the growth and characterization of non-epitaxial but (100)-highly textured BaBiO3 thin films on silicon substrates. We have found the deposition conditions that optimize the texture, and show that the textured growth is favoured by the formation of a BaO layer at the first growth stages. X-ray diffraction Φ-scans, together with the observation that the same textured growth is found on films grown on Pt and SiO2 buffered Si, demonstrate the absence of epitaxy. Finally, we have shown that our (100)-oriented BaBiO3 films can be used as suitable buffers for the growth of textured heterostructures on silicon, which could facilitate the integration of potential devices with standard electronics.

The LabOSat collaboration (acronym for “Laboratory On a Satellite”) aims to increase the Technology Readiness Level (TRL) of electronic devices and components for space-borne applications. We have developed a single-board electronic platform which is able to operate in space conditions. This board harbors Devices Under Test and performs electric experiments on them. Since 2014, we have participated in six satellite missions (Satellogic small satellites) in Low Earth Orbits, in which we studied the performance of electronic devices such as resistive switching memories and dosimeters based on field-effect transistors. In this work we present our efforts to increase the TRL of Silicon Photomultipliers (SiPMs). In early 2019 we have integrated four 6-mm SiPMs into a 40-kg satellite to study their performance in space. Each SiPM was encapsulated into individual light-tight aluminum housings, which included LEDs for excitation. The SiPMs and the LEDs are operated in DC current mode. Besides the SiPMs current and voltage measurements, the experiment also collects telemetry parameters like temperature, timestamp and orbital position. Fil: Barella, Mariano. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina Fil: Burroni, Tomás Ignacio. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Carsen, Irina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Far, Mónica. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Ferreira Chase, Tomás Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Finazzi, Lucas. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gomez Marlasca, Fernando. Comisión Nacional de Energía Atómica; Argentina Fil: Izraelevitch, Federico Hernán. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Levy, Pablo. Comisión Nacional de Energía Atómica; Argentina Fil: Sanca, Gabriel. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina

Understanding the effect of fabrication conditions on domain wall (DW) motion in thin films with perpendicular magnetization is a mandatory issue in order to tune their properties aiming to design spintronics devices based on such phenomenon. In this context, the present work intends to show how different growth conditions may affect DW motion in the prototypical system Pt/Co/Pt. The trilayers were deposited by dc sputtering, and the parameters varied in this study were the Co thickness, the substrate roughness and the base pressure in the deposition chamber. Magneto-optical Kerr effect-based magnetometry and microscopy combined with x-ray reflectometry, atomic force microscopy and transmission electron microscopy were adopted as experimental techniques. This permitted us to elucidate the impact on the hysteresis loops and on the DW dynamics, produced by different growth conditions. As other authors, we found that Co thickness is strongly determinant for both the coercive field and the DW velocity. On the contrary, the topographic roughness of the substrate and the base pressure of the deposition chamber evidence a selective impact on the nucleation of magnetic domains and on DW propagation, respectively, providing a tool to tune these properties.

LabOSat (acronym for “Laboratory On a Satellite”) is a type of electronic platform designed to perform experiments in harsh, remote environments. Up to now, LabOSat platforms have been used mainly for characterizing and validating custom and commercial electronic devices at Low Earth Orbits (LEO). Many of these platforms are running experiments aboard ÑuSat satellites, which are built and operated by Argentine company Satellogic. A brief description of LabOSat platforms is presented here, along with details of their validation both at LEO and at a nuclear reactor. The electrical characterization of custom non-volatile memory cells — as performed by a LabOSat platform at LEO — is also described, and the results of such experiment are compared with results obtained on Earth. The memory cells studied were TiO2-based and La1/3Ca2/3MnO3-based ReRAM devices. Fil: Barella, Mariano. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sanca, Gabriel Andrés. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Gomez Marlasca, Fernando. Comisión Nacional de Energía Atómica; Argentina Fil: Acevedo, W. Román. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Rubi, Diego. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: García Inza, Mariano Andrés. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Laboratorio de Física de Dispositivos Microelectrónica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; Argentina International Forum on Advances in Radiation Physics Buenos Aires Argentina Università di Bologna

Conductive-tip atomic force microscopy (CAFM) was used to explore the effects of high electric fields on silver nanoparticle (NP) arrays embedded inside the pores of mesoporous TiO2 thin films (MTF). A controlled local modification of the distribution of Ag nanoparticles inside the MTF and their electronic transport properties was carried out. The process is driven by strong electrochemically induced Ag+ migration and reduction inside the pores localized around the CAFM tip. Depending on the experimental parameters, we were able to induce drastic and violent changes, both at the surface and at the MTF/Si interface, that is, through the whole scanned region. Therefore, the results reported in this work contribute to the design and development of novel metal NP-based devices at the micro- and nanoscale. Fil: Linares Moreau, María de Las Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto Sabato; Argentina. Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia.; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones No Nucleares. Gerencia Física (CAC). Departamento de Física de la Materia Condensada; Argentina Fil: Martínez, Eduardo David. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia.; Argentina Fil: Fuertes, María Cecilia. Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia.; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Instituto Sabato; Argentina Fil: Zelcer, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Granell, Pablo Nicolás. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; Argentina Fil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones No Nucleares. Gerencia Física (CAC). Departamento de Física de la Materia Condensada; Argentina. Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia.; Argentina Fil: Soler Illia, Galo Juan de Avila Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina Fil: Granja, Leticia Paula. Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia.; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones No Nucleares. Gerencia Física (CAC). Departamento de Física de la Materia Condensada; Argentina

Atomic layer deposition (ALD) is a standard technique employed to grow thin-film oxides for a variety of applications. We describe the technique and demonstrate its use for obtaining memristive devices. The metal/insulator/metal stack is fabricated by means of ALD-grown HfO2, deposited on top of a highly doped Si substrate with an SiO2 film and a Ti electrode. Enhanced device capabilities (forming free, self-limiting current, non-crossing hysteretic current-voltage features) are presented and discussed. Careful analysis of the stack structure by means of X-ray reflectometry, atomic force microscopy, and secondary ion mass spectroscopy revealed a modification of the device stack from the intended sequence, HfO2/Ti/SiO2/Si. Analytical studies unravel an oxidation of the Ti layer which is addressed for the use of the ozone precursor in the HfO2 ALD process. A new deposition process and the model deduced from impedance measurements support our hypothesis: the role played by ozone on the previously deposited Ti layer is found to determine the overall features of the device. Besides, these ALD-tailored multifunctional devices exhibit rectification capability and long enough retention time to deserve their use as memory cells in a crossbar architecture and multibit approach, envisaging other potential applications.

In this paper a CMOS reading circuit for memristor-based RRAM (Resistive Random Access Memory) cell is described. Simulations for one cell, 4 by 4 nMOS-accessed-array and extension to N by N nMOS-accessed-array are presented. The proposed circuit is based on CMOS inverters, which result in a simple low area architecture and in a non-destructive operation. Resistive switching memristor is used as reading reference. Simulations were performed in $0.5\ \mu \text{m}$ and 180 nm CMOS technology and using memristor model available in bibliography.

Microfluidic devices are a new platform for Enhanced Oil Recovery (EOR) assays. A successful oil recoveryin a reservoir can be different in another, hence the importance of a methodology for assessment prior toinjection. In the current study, micro and nanotechnology techniques were applied to develop EOR assays.The EOR chips simulated the phenomena occurred in micro-nano scale reservoirs. In general, the first step ofthe experiments corresponded to fill the microchannels with oil, then was injected water at constant flow rateuntil oil recovery ceases and finally was injected polymer or CDG. The recovery behaviors of the fluids werestudied by digital image analysis. Results allowed obtaining oil recovery for each evaluated fluid. Theoptimum configuration of the microchannels showed 80% of oil residual saturation after water injection.Keywords: EOR, poral volume, microgels and polymers, microfuidic devices. Fil: Rosero Yánez, Gustavo Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Peñaherrera Pazmiño, Ana Belén. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Olmos Carreno, Carol Maritza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Boschan, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina Fil: Granell, Pablo Nicolás. Instituto Nacional de Tecnología Industrial; Argentina Fil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lasorsa, Carlos Alberto. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina

En el presente trabajo se estudió el proceso de fabricación de una serie de macroporos sobre obleas de silicio cristalino mediante la técnica wet etching. Se evaluó la incidencia de distintos factores como el voltaje, la temperatura y el agente de frenado sobre las características específicas de la formación. A partir de los datos obtenidos de la evolución de las corrientes fue posible estandarizar el proceso y determinar el momento de formación del poro, esencial en cuanto a la disponibilidad de un método compatible con las exigencias de la industria. Finalmente, se concluyó que para la fabricación de poros en forma controlada, las condiciones óptimas corresponden a una temperatura de 84 ˚C, HCl como agente de frenado y voltajes de 0,1V, 0,5V y 1V respectivamente. Los anteriores resultados son de gran importancia en los campos de la medicina y la biología en relación a la utilidad de los poros como dispositivos de sensado. In the present work, the fabrication process of a set of micropores on crystalline silicon wafers manufactured through wet etching technique was studied. The influence of different control factors such as voltage, temperature and braking agent on the specific characteristics of formation was evaluated. An exhaustive analysis of the evolution of electric currents during the fabrication made possible to standardize the process and determine the pore-formation time, essential feature considering the exigent requirements of industry. Finally, it was concluded that optimum conditions for a controlled fabrication of pores correspond to a temperature of 84 ˚C, HCl as a braking agent and voltages of 0,1V, 0,5V and 1V respectively. The above results are of great importance in different fields, such as biology or medicine, in relation to the utility of pores as sensing devices. Fil: Der, Manuel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Olmos Carreno, Carol Maritza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Rosero Yánez, Gustavo Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Santizo Huerta, Itzel Erándeni. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Fernandez, Tamara. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Dieguez, Maria. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Grupo Vinculado Instituto de Genética "Ewald A. Favret" al Iabimo | Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular. Grupo Vinculado Instituto de Genética "Ewald A. Favret" al Iabimo; Argentina Fil: Sacco, Francisco. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Grupo Vinculado Instituto de Genética "Ewald A. Favret" al Iabimo | Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular. Grupo Vinculado Instituto de Genética "Ewald A. Favret" al Iabimo; Argentina Fil: Granell, Pablo Nicolás. Instituto Nacional de Tecnología Industrial; Argentina Fil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina Fil: Lerner, Betiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Lasorsa, Carlos Alberto. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina Fil: Perez, Maximiliano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina

We report on the fabrication and characterization of La2/3Ca1/3MnO3 manganite-based memristive devices. Polycrystalline manganite thin films were grown by Pulsed Laser Deposition, while metallic electrodes were deposited by sputtering. We show that, depending on the polarity of the initial electroforming, both clockwise and anti-clockwise current-voltage curves can be obtained. We attribute this behavior to the coexistence of different resistive switchingmechanisms.We finally evaluate the electrical behavior of our devices after irradiation with high energy oxygen ions. We find no significant difference in the dielectric breakdown voltages between irradiated and non-irradiated devices, indicating that they may present radiation hardness and could be therefore appropriate for space or nuclear applications. Fil: Rubi, Diego. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Kalstein, Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Roman Acevedo, Wilson Stibens. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Ghenzi, Néstor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Quinteros, Cynthia Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Mangano, E.. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario. Unidad Técnica de Micro y Nano Sistemas; Argentina Fil: Granell, Pablo Nicolás. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario. Unidad Técnica de Micro y Nano Sistemas; Argentina Fil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario. Unidad Técnica de Micro y Nano Sistemas; Argentina Fil: Marlasca, F. G.. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Suarez, Sergio Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Bernardi, Guillermo Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Albornoz, C.. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Leyva de Guglielmino, Ana Gabriela. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Levy, Pablo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina

We study the crystalline structure and superconducting properties of γ-Mo2N thin films grown by reactive DC sputtering on AlN buffered Si (001) substrates. The films were grown at room temperature. The microstructure of the films, which was studied by X-ray diffraction and transmission electron microscopy, shows a single-phase with nanometric grains textured along the (200) direction. The films exhibit highly uniform thickness in areas larger than 20 × 20 μm2. The superconducting critical temperature Tc is suppressed from 6.6 K to ≈ 3.0 K when the thickness decreases from 40 nm to 5 nm. The residual-resistivity ratio is slightly smaller than 1 for all the films, which indicates very short electronic mean free path. The films are in the superconducting dirty limit with upper critical field Hc2 (0) ≈ 12 T for films with thickness of 40 nm, and 9 T for films with thickness of 10 nm. In addition, from the critical current densities Jc in the vortex-free state, we estimate a penetration depth λ(0) ≈ (800 ± 50) nm and a thermodynamic critical field Hc (0) = (500 ± 80 Oe). Fil: Haberkorn, Nestor Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Bengió, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Troiani, Horacio Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Suarez, Sergio Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Pérez, Pablo Daniel. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Granell, Pablo Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina Fil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina Fil: Sirena, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Guimpel, Julio Juan. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

We report the influence of crystalline defects introduced by 6 MeV $^{16}$O$^{3+}$ irradiation on the critical current densities J$_c$ and flux creep rates in 1.3 $\mu$m thick GdBa$_2$Cu$_3$O$_{7-d}$ coated conductor produced by co-evaporation. Pristine films with pinning produced mainly by random nanoparticles with diameter close to 50 nm were irradiated with doses between 2x10$^{13}$ cm$^{-2}$ and 4x10$^{14}$ cm$^{-2}$. At temperatures below 40 K with the magnetic field applied parallel (H//c) and at 45{\deg} (H//45{\deg}) to the c-axis, the in-field J$_c$ dependences can be significantly improved by irradiation. For doses of 1x10$^{14}$ cm$^{-2}$ the J$_c$ values at $\mu$$_0$H = 5 T are doubled without affecting significantly the J$_c$ at small fields. Analyzing the flux creep rates as function of the temperature in both magnetic field configurations, it can be observed that the irradiation suppresses the peak associated with double-kink relaxation and increases the flux creep rates at intermediate and high temperatures. Under 0.5 T, the flux relaxation for H//c and H//45{\deg} in pristine films presents characteristic glassy exponents $\mu$ = 1.63 and $\mu$ = 1.45, respectively. For samples irradiated with 1x10$^{14}$ cm$^{-2}$, these values drop to $\mu$ = 1.45 and $\mu$ =1.24, respectively., Comment: 19 pages, 7 figures

Phone: þ34 943 574012, Fax: 34 943 574001We present performance characteristics of nanoscaled cobaltphthalocyanine (CoPc)-based organic field-effect transistors(OFETs) as a function of channel length. We found a channellength range which maximizes the field effect mobility in atrade-off between the decrease in the number of organic grainboundaries and the increase of the electrode–organic contactregion. Further reduction of channel length is limited by fringecurrents, which lead to an increased off current and to adegradation of the sub-threshold slope. From this, we definean optimal channel length of 280nm to 1mm for applicationsin submicrometric CoPc-based OFETs. Our results are particu-larly relevant for the miniaturization of chemical sensingOFETs, where metal phthalocyanines have proven to beexcellentcandidatesforthefabricationofthetransistorchannel.

The objective of this study was to demonstrate the possibility of using 1-butanol to reliably detect the open-pore current of pyramidal solid-state nanopores produced in silicon wafers. The nanopores were produced through controlled pore formation by neutralizing an etchant (KOH) with a strong acid (HCl). Since nanopores produced by this method are deeper than those made in nanometer-thick membranes, they behave as nanochannels. As a consequence, the open-pore current detection is more challenging. Thus, we report that low amounts of butanol considerably aid in the detection of the open-pore current of nanopores. Instituto de Genética Fil: Vega, Milena. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Universidad de Salamanca. Departamento de Ingeniería Química; España Fil: Perez, Maximiliano. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina Fil: Granell, Pablo. Instituto Nacional de Tecnología Industrial; Argentina Fil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina Fil: Wloka, Carsten. University of Groningen. Groningen Biomolecular Sciences and Biotechnology Institute; Países Bajos Fil: Maglia, Giovanni. University of Groningen. Groningen Biomolecular Sciences and Biotechnology Institute; Países Bajos Fil: Dieguez, María José. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina Fil: Del Valle, Eva María. Universidad de Salamanca. Departamento de Ingeniería Química; España Fil: Lasorsa, Carlos. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina Fil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina

In this work the characteristics and performance of LabOSat platform to carry out experiments over electronic devices in aggressive environments are described. Configurable, portable, low weight and low cost are the main features. First measurements made in our laboratory are presented before testing in space.

We report on non-volatile memory devices based on multifunctional manganites. The electric field induced resistive switching of Ti/$La_{1/3}$$Ca_{2/3}$Mn$O_3$/n-Si devices is explored using different measurement protocols. We show that using current as the electrical stimulus (instead of standard voltage-controlled protocols) improves the electrical performance of our devices and unveils an intermediate resistance state. We observe three discrete resistance levels (low, intermediate and high), which can be set either by the application of current-voltage ramps or by means of single pulses. These states exhibit retention and endurance capabilities exceeding $10^4$ s and 70 cycles, respectively. We rationalize our experimental observations by proposing a mixed scenario were a metallic filament and a Si$O_x$ layer coexist, accounting for the observed resistive switching. Overall electrode area dependence and temperature dependent resistance measurements support our scenario. After device failure takes place, the system can be turned functional again by heating up to low temperature (120 C), a feature that could be exploited for the design of memristive devices with self-healing functionality. These results give insight into the existence of multiple resistive switching mechanisms in manganite-based memristive systems and provide strategies for controlling them., 17 pages, 7 figures, to appear in Phys. Lett. A

We study micrometer-sized organic field-effect transistors with either Pd or NiFe metallic electrodes. Neither of these materials is commonly used in organic electronics applications, but they could prove to be particularly advantageous in certain niche applications such as organic spintronics. Using organic semiconductors with different carrier transport characteristics as active layer, namely n-type C60 fullerene and p-type Pentacene, we prove that Pd (NiFe) is a very suitable electrode for p- (n-) type semiconductors. In particular, we characterized devices with channel lengths in the order of the micrometer, a distance which has allowed us to evaluate the electronic behavior in a regime where the interfacial problems become predominant and it is possible to reach elevated longitudinal electric fields. Our experimental results agree well with a simple model based on rigid energy levels.

We study the propagation of mid-infrared surface plasmons on non-tapered and tapered two-wire transmission lines on Si and CaF2 substrates, the two materials representing substrates with large and small refractive index, respectively. A comparative numerical study predicts a larger effective wavelength and an increased propagation length (i.e. weaker damping) for the CaF2 substrate. By near-field microscopy we image the near-field distribution along the transmission lines and experimentally verify surface plasmon propagation. Amplitude- and phase-resolved near-field images of a non-tapered transmission line on CaF2 reveal a standing wave pattern caused by back-reflection of the surface plasmons at the open-ended transmission line. Calculated and experimental near-field images of tapered transmission lines on Si and CaF2 demonstrate that for both substrates the mid-IR surface plasmons are compressed when propagating along the taper. Importantly, the nanofocus at the taper apex yields a stronger local field enhancement for the low-refractive index substrate CaF2. We assign the more efficient nanofocusing on CaF2 to the weaker damping of the surface plasmons.

Spintronics based on ferromagnetic metals and organic semiconductors has attracted great interest in recent years. Molecular-based spintronic devices, such as magnetic tunnel junctions, have been demonstrated with performances competing with those of conventional inorganic devices. Still, there is huge margin for improvement, as many details about the injection of spin-polarized electrons into the molecular layer remain not completely understood. In order to achieve better understanding and control of the physical mechanisms, it is necessary to explore various combinations of ferromagnetic metals and organic semiconductors. In this letter, we study the properties of the combination between the ferromagnetic metal NiFe (commonly known as Permalloy or Py) and the molecular system C 60 . We produced C 60 /Py bilayers and characterized them structurally, electrically and magnetically. The C 60 films grow smoothly on both Py and SiO 2 substrates, and we estimate that a 5-nm-thick C 60 film covers completely the surface underneath without leaving pinholes and can be therefore used in a vertical device, as confirmed by electrical characterization. Furthermore, the C 60 film is robust against the deposition of the top metal electrode, being the intermixing layer of only 1–2 nm at the C 60 /Py interface. Finally, we show that the magnetic properties of Py are not affected by the deposition sequence, and that a 5-nm-thick Py layer on top of a C 60 layer keeps its magnetic properties intact. These results show that the combination between Py and C 60 provides a robust template platform for the development of molecular spintronics, and can be used later on for more sophisticated investigations, such as the role of the interfaces in the spin injection.

An unprecedented control of the spectral response of plasmonic nanoantennas has recently been achieved by designing structures that exhibit Fano resonances. This new insight is paving the way for a variety of applications, such as biochemical sensing and surface-enhanced Raman spectroscopy. Here we use scattering-type near-field optical microscopy to map the spatial field distribution of Fano modes in infrared plasmonic systems. We observe in real space the interference of narrow (dark) and broad (bright) plasmonic resonances, yielding intensity and phase toggling between different portions of the plasmonic metamolecules when either their geometric sizes or the illumination wavelength is varied. © 2011 American Chemical Society., P.A.-G, M.S., P.S., P.A., and R.H. acknowledge support from the European FP7 project “Nanoantenna” (FP7-HEALTH-F5-2009-241818-NANOANTENNA) and the National Project MAT2009-08393 from the Spanish Ministerio de Ciencia e Innovacion. M.S. and P.S. acknowledges financial support from “Programa de Formación de Personal Investigador” promoted by the Department of Education, Universities and Research of the Basque Government. P.N. and H.S. acknowledge support from the Robert A. Welch foundation (C-1222), the US Department of Defense NSEFF program (N00244-09-1-0067), and the Office of Naval Research (N00244-09-1-0989). C.W., N.A., A. K., and G.S. acknowledge support from the Office of Naval Research (N00014-10-1-0929) and the Air Force Research Laboratory.

We have studied the influence of intrinsic and extrinsic defects in the magnetic and electrical transport properties of Co-doped ZnO thin films. X ray absorption measurements show that Co substitute Zn in the ZnO structure and it is in the 2+ oxidation state. Magnetization (M) measurements show that doped samples are mainly paramagnetic. From M vs. H loops measured at 5 K we found that the values of the orbital L and spin S numbers are between 1 and 1.3 for L and S = 3/2, in agreement with the representative values for isolated Co 2+. The obtained negative values of the Curie-Weiss temperatures indicate the existence of antiferromagnetic interactions between transition metal atoms., Comment: To be published in Journal of Materials Science

International audience; The conduction characteristics of La 1/3 Ca 2/3 MnO 3 (LCMO) films grown by pulsed laser deposition were investigated. The devices exhibit bipolar resistive switching effect with intermediate conduction states achievable by the application of positive and negative voltage ramps. The I-V curves are modeled using a nonlinear memristive approach based on the double-diode equation and the solution of the generalized logistic differential equation. © 2015 IEEE.

Transparent pure and Fe-doped SnO 2 thin films were grown by pulsed laser deposition technique on LaAlO 3 substrates. X-ray diffraction shows that the films are polycrystalline and have the rutile structure. Surprisingly, the pure film presents magnetic-like behavior at room temperature with a saturated magnetization of almost one-third of the doped film (∼3.6 and 11.3 emu/g, respectively) and its magnetization could not be attributed to any impurity phase. Taking into account the magnetic moment measured in the pure film, the effective contribution of the impurity in the doped one can be inferred to be ∼2 μ B per Fe atom. A large magnetic moment was also predicted by an ab initio calculation in the doped system, which increases if an oxygen vacancy is present near the Fe impurity.

In this work, we investigate the polarity-dependent Electric Pulses Induced Resistive (EPIR) switching phenomenon in thin films driven by electric pulses. Thin films of 0.5Ca0.5MnO3 (manganite) were deposited by PLD on Si substrate. The transport properties at the interface between the film and metallic electrode are characterized in order to study the resistance switching. Sample thermal treatment and electrical field history are important to be considered for get reproducible EPIR effect. Carriers trapping at the interfaces are considered as a possible explanation of our results.

Transition-Metal-doped TiO2 thin films, with nominal composition Ti₀.₉TM₀₁O₂-δ (TM = Mn, Fe, Co, Ni, Cu), were grown by pulsed laser deposition (PLD), in order to study the role of dopants in the origin and significance of room temperature ferromagnetism in these systems. The crystallographic structures and their magnetic properties were characterized and the experimental results are compared to ab-initio calculations previously reported. The films are ferromagnetic at room temperature in the cases of Fe, Co, Ni and even Cu impurities, but not in the case of Mn doping. Our results support the hypothesis that oxygen vacancies play a key role in the origin of magnetism in doped TiO2 films, and can explain the diversity of magnetic moments observed experimentally for films grown under different conditions., Instituto de Física La Plata

We report on magnetotransport properties on La_(0.7)Sr_(0.3)MnO_(3)/MgO/Fe tunnel junctions grown epitaxially on top of (001)-oriented SrTiO_(3) substrates by sputtering. It is shown that the magnetoresistive response depends critically on the MgO/Fe interfacial properties. The appearance of an FeOX layer by the interface destroys the 1 symmetry filtering effect of the MgO/Fe system and only a small negative tunneling magnetoresistance (TMR) (∼ −3 %) is measured. However, in annealed samples a switchover from positive TMR (∼ +25% at 70 K) to negative TMR (∼ −1 %) is observed around 120 K. This change is associated with the transition from semiconducting at high T to insulating at low T taking place at the Verwey transition (TV ∼ 120 K) in Fe3O4, thus suggesting the formation of a very thin slab of magnetite at the MgO/Fe interface during annealing treatments. These results highlight the relevance of interfacial properties on the tunneling conduction process and how it can be substantially modified through appropriate interface engineering.

The distribution of boron in tissue samples coming from boron neutron capture therapy protocols can be determined through the analysis of its autoradiography image on a nuclear track detector. A more precise knowledge of boron atom location on the microscopic scale can be attained by the observation of nuclear tracks superimposed on the sample image on the detector. A method to produce an “imprint” of cells cultivated on a polycarbonate detector was developed, based on the photodegradation properties of UV-C radiation on this material. Optimal conditions to generate an appropriate monolayer of Mel-J cells incubated with boronophenylalanine were found. The best images of both cells and nuclear tracks were obtained for a neutron fluence of 1013cm−2, 6 h UV-C (254 nm) exposure, and 4 min etching time with a KOH solution. The imprint morphology was analyzed by both light and scanning electron microscopy. Similar samples, exposed to UV-A (360 nm) revealed no cellular imprinting. Etch pits were present only inside the cell imprints, indicating a preferential boron uptake (about threefold the incubation concentration). Comparative studies of boron absorption in different cell lines andin vitroevaluation of the effect of diverse boron compounds are feasible with this methodology.

We report the electrical transport properties of conducting/insulator/conducting heterostructures by studying current-voltage IV curves at room temperature. The measurements were obtained on tunnel junctions with different areas (900, 400 and 100 μm2) using a conducting atomic force microscope. Trilayers with GdBa2Cu3O7 (GBCO) as the bottom electrode, SrTiO3 or BaTiO3 (thicknesses between 1.6 and 4 nm) as the insulator barrier, and GBCO or Nb as the top electrode were grown by DC sputtering on (100) SrTiO3 substrates For SrTiO3 and BaTiO3 barriers, asymmetric IV curves at positive and negative polarization can be obtained using electrodes with different work function. In addition, hysteretic IV curves are obtained for BaTiO3 barriers, which can be ascribed to a combined effect of the FE reversal switching polarization and an oxygen vacancy migration. For GBCO/BaTiO3/GBCO heterostructures, the IV curves correspond to that expected for asymmetric interfaces, which indicates that the disorder affects differently the properties at the bottom and top interfaces. Our results show the role of the interface disorder on the electrical transport of conducting/insulator/conduction heterostructures, which is relevant for different applications, going from resistive switching memories (at room temperature) to Josephson junctions (at low temperatures). Fil: Navarro Fernández, Henry Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Sirena, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Gonzalez Sutter, Jesus Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Troiani, Horacio Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: del Corro, Pablo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Granell, Pablo Nicolás. Instituto Nacional de Tecnología Industrial; Argentina Fil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Haberkorn, Nestor Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina

We report on the influence of oxygen stoichiometry on the vortex creep mechanism of GdBa2Cu3O x -coated conductors produced by co-evaporation. The oxygen stoichiometry of the films, x, was modified in a controlled way between 6.85 and 7, which resulted in systematic and reversible control of the superconducting critical temperature between about 78 and 93 K. The change in the oxygen stoichiometry produces a strong reduction in the self-field critical current densities J c without significantly modifying the power-law dependence at intermediate magnetic fields, which indicates a negligible contribution of oxygen vacancies to the pinning. In addition, the characteristic glassy exponent ? shows a systematic diminution from about 1.63 at x?=?7 to about 1.12 at x?=?6.85. The results are compared with those obtained for proton- and oxygen-irradiated films, in which the vortex dynamics is determined by a balance between the improved pinning, originating from nanocluster inclusion, and the suppressed superconducting properties due to disorder in the nanoscale.

We report the fabrication of single electron transistors (SETs) by feedback-controlled electromigration of palladium and palladium-nickel alloy nanowires. We have optimized a gradual electromigration process for obtaining devices consisting of three terminals (source, drain and gate electrodes), which are capacitively coupled to a metallic cluster of nanometric dimensions. This metal nanocluster forms into the inter-electrode channel during the electromigration process and constitutes the active element of each device, acting as a quantum dot that rules the electron flow between source and drain electrodes. The charge transport of the as-fabricated devices shows Coulomb blockade characteristics and the source to drain conductance can be modulated by electrostatic gating. We have thus achieved the fabrication and in situ measurement of palladium-based SETs inside a liquid helium cryostat chamber. Fil: Arzubiaga, L.. CIC nanoGUNE; España Fil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Llopis, R.. CIC nanoGUNE; España Fil: Casanova, F.. CIC nanoGUNE; España. IKERBASQUE; España Fil: Hueso, Luis E.. CIC nanoGUNE; España. IKERBASQUE; España

The energetics of metal/molecular semiconductor interfaces plays a fundamental role in organic electronics, determining the performance of very diverse devices. So far, information about the energy level alignment has been most commonly gained by spectroscopy techniques that typically require experimental conditions far from the real device operation. Here we demonstrate that a simple three-terminal device allows the acquisition of spectroscopic information about the metal/molecule energy alignment in real operative condition. As a proof of principle, we employ the proposed device to measure the energy barrier height between different clean metals and C60 molecules and we recover typical results from photoemission spectroscopy. The device is designed to inject a hot electron current directly into the molecular level devoted to charge transport, disentangling the contributions of both the interface and the bulk to the device total resistance, with important implications for spintronics and low-temperature physics. Fil: Gobbi, M.. CIC nanoGUNE; España. Université de Strasbourg; Francia Fil: Pietrobon, L.. CIC nanoGUNE; España Fil: Atxabal, A.. CIC nanoGUNE; España Fil: Bedoya Pinto, A.. CIC nanoGUNE; España Fil: Sun, X.. CIC nanoGUNE; España Fil: Golmar, Federico. CIC nanoGUNE; España. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Llopis, R.. CIC nanoGUNE; España Fil: Casanova, F.. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; España Fil: Hueso, L. E.. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; España

Graphene plasmons promise unique possibilities for controlling light in nanoscale devices and for merging optics with electronics. Here we introduce a versatile platform technology based on resonant optical antennas and conductivity patterns for launching and controlling of propagating graphene plasmons, constituting an essential step for the development of graphene plasmonic circuits. We demonstrate the launching and focusing of infrared graphene plasmons with geometrically tailored antennas, and how they refract when passing through a 2-dimensional conductivity pattern, here a prism-shaped bilayer. To that end, we directly map the graphene plasmon wavefronts using an imaging method that will also benefit the testing of future design concepts for nanoscale graphene plasmonic circuits and devices Fil: Alonso Gonzalez, P. CIC nanoGUNE. San Sebastian; España Fil: Nikitin, A.Y.. CIC nanoGUNE. San Sebastian; España. IKERBASQUE. Bilbao; España Fil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. CIC nanoGUNE. San Sebastian; España. Instituto Nacional de Tecnología Industrial; Argentina. Universidad Nacional de San Martín; Argentina Fil: Centeno, A. Graphenea SA. San Sebastian; España Fil: Pesquera, A. Graphenea SA. San Sebastian; España Fil: Velez, S. CIC nanoGUNE. San Sebastian; España Fil: Chen, J. CIC nanoGUNE. San Sebastian; España Fil: Navickaite, G. Institut de Ciéncies Fotoniques. Barcelona; España Fil: Koppens, F.. Institut de Ciéncies Fotoniques. Barcelona; España Fil: Zurutuza, A. Graphenea SA. San Sebastian; España Fil: Casanova, F.. CIC nanoGUNE. San Sebastian; España. IKERBASQUE. Bilbao; España Fil: Hueso, L.. CIC nanoGUNE. San Sebastian; España. IKERBASQUE. Bilbao; España Fil: Hillenbrand, R.. IKERBASQUE. Bilbao; España. CIC nanoGUNE. San Sebastian; España

This work probes the relevance of oxygen vacancies in the formation of local ferromagnetic coupling between Fe ions at octahedral sites in zinc ferrites. This coupling gives rise to a ferrimagnetic ordering with the Curie temperatures above room temperature in an otherwise antiferromagnetic compound. This conclusion is based on experimental results from x-raymagnetic circular dichroismmeasurements at the Fe L2,3 edges and magnetization measurements performed on zinc ferrites, nanoparticles, and films, with different cation distributions and oxygen vacancy concentrations. Our observations are confirmed by density-functional-theory calculations and indicate that the enhanced ferrimagnetic response observed in some nominally nonmagnetic or antiferromagnetic ferrites can be taken as a further example of the defect-induced magnetism phenomenon. Fil: RodrÍguez Torres, Claudia Elena. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina Fil: Pasquevich, Gustavo Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina Fil: Mendoza Zélis, Pedro. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina Fil: Golmar, Federico. CIC Nanogune; España. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pérez, Silvia Inés. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Nayak, Sanjeev K.. Martin Luther University Halle-Wittenberg; Alemania Fil: Adeagbo, Waheed A.. Martin Luther University Halle-Wittenberg; Alemania Fil: Hergebert, Wolfram. Martin Luther University Halle-Wittenberg; Alemania Fil: Hoffmann, Martin. Martin Luther University Halle-Wittenberg; Alemania. Institut Max Planck of Microstructure Physics; Alemania Fil: Ernst, Arthur. Institut Max Planck of Microstructure Physics; Alemania Fil: Esquinazi, P.. University of Leipzig; Alemania Fil: Stewart, Silvana Jacqueline. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina

Transparent pure and Cu-doped (2.5, 5 and 10 at.%) anatase TiO 2 thin films were grown by pulsed laser deposition technique on LaAlO 3 substrates. The samples were structurally characterized by X-ray absorption spectroscopy and X-ray diffraction. The magnetic properties were measured using a SQUID. All films have a FM-like behaviour. In the case of the Cu-doped samples, the magnetic cycles are almost independent of the Cu concentration. Cu atoms are forming CuO and/or substituting Ti in TiO 2 . The thermal treatment in air promotes the CuO segregation. Since CuO is antiferromagnetic, the magnetic signals present in the films could be assigned to Cu substitutionally replacing cations in TiO 2 .

Resistance random access memory (ReRAM) is considered a promising candidate for the next generation of non-volatile memory. In this work, we fabricate Co/HfO2/Ti devices incorporating atomic-layer-deposited HfO 2 thin films as the active material grown under different atomic layer deposition (ALD) conditions. We focus on analyzing the effect of ALD conditions on the resistive switching behaviour of the devices. Electrical characterization reveals a particular non-crossing current-voltage curve and bipolar resistive switching behaviour. Device memory properties were confirmed by stability and retention measurements as well as voltage pulses, by which logical computational processes were conducted. X-ray photoelectron spectroscopy combined with electrical measurements demonstrates that the presence of Hf sub-oxides at the interface with the underlying Ti layer is required in order to achieve a stable switching device. The ability of Ti to scavenge oxygen from the HfO2 is shown to be affected by the ALD conditions. This journal is © the Partner Organisations 2014., We also acknowledge funding support from Juan de la Cierva Program JCI-2010-07837 and by projects MAT2009-08494, MAT2010-21156-C03-03 and MAT2012-37638 from the Spanish Ministry of Science, by the Basque Government through Project nos PI2011-1 and IT-621-13 as well as a Marie Curie Reintegration Grant (ITAMOSCINOM) from the European Commission.

We report on the fabrication and characterization of metal/insulator/metal capacitor like devices, with both rectifying and hysteretic features. Devices are formed by two junctions, Ti/HfO2 and Co/HfO2. Each junction exhibits highly repetitive hysteretic I-V curves with a sharp transition from a high to a low resistance state (3–4 orders of magnitude jump). The opposite transition (from low to high) is induced by polarity reversal. The rectifying non-crossing characteristics of the I-V branches denote their potential use as a multifunctional device, acting as a built-in rectifier and memory cell in a single device. Based on the phenomenological model description by Zazpe et al. [Appl. Phys. Lett. 103, 073114 (2013)], we propose a circuital equivalent representation supported on switchable rectifying junctions. By exploring different electrode connections, we disentangle the role of the bulk transport in HfO2 devices. Fil: Quinteros, Cynthia Paula. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Zaspe, R.. CIC nanoGUNE; España Fil: Marlasca, F. G.. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Casanova, F.. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; España Fil: Stoliar, Pablo Alberto. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Centre National de la Recherche Scientifique; Francia. Universite de Nantes; Francia Fil: Hueso, L.. Fundación Vasca para la Ciencia; España. CIC nanoGUNE; España Fil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Organic semiconductors, characterized by weak spin-scattering mechanisms, are attractive materials for those spintronic applications in which the spin information needs to be retained for long times. Prototypical spin-valve devices employing organic interlayers sandwiched between ferromagnetic materials possess a figure of merit (magnetoresistance (MR)) comparable to their fully inorganic counterparts. However, these results are a matter of debate as the conductivity of the devices does not show the expected temperature dependence. Here we show spin valves with an interlayer of bathocuproine in which the transport takes place unambiguously through the organic layer and where the electron spin coherence is maintained over large distances (>60 nm) at room temperature. Additionally, the devices show excellent air stability, with MR values almost unaltered after 70 days of storage under ambient conditions, making bathocuproine an interesting material for future spintronic applications. Fil: Sun, Xiangnan. CIC nanoGUNE; España Fil: Gobbi, Marco. Université de Strasbourg; Francia. CIC nanoGUNE; España Fil: Bedoya Pinto, Amilcar. CIC nanoGUNE; España Fil: Txoperena, Oihana. CIC nanoGUNE; España Fil: Golmar, Federico. CIC nanoGUNE; España. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Llopis, Roger. CIC nanoGUNE; España Fil: Chuvilin, Andrey. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; España Fil: Casanova, Félix. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; España Fil: Hueso, Luis E.. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; España

Epitaxial ZnFe2O4 thin films were deposited on monocrystalline MgO substrate by dc-sputtering. Ferrites were grown from Zn-O and Fe-O multilayers starting from metallic targets in oxygen atmosphere. The number and thickness of layers were varied holding constant the total thickness (50 nm) and sample stoichiometry (Fe/Zn=2). The samples were structural and magnetically characterized by X-ray diffraction and magnetic measurements, respectively. Thin film fabricated using 20 bilayers of thickness 3 nm present a magnetic behavior similar to bulk ZnFe2O4, with a Néel temperature TN=10.5 K. The magnetic behavior of those films obtained from thicker bilayers (6 and 10 nm) is characterized by the coexistence of antiferro and ferromagnetic regions. This is probably due to the inhomogeneities in Zn and Fe distributions caused by an incomplete interdiffusion process prevented by the relatively large multilayer thickness. These inhomogeneities probably generate zinc-iron position replacements and interrupt the long-range antiferromagnetic order, giving rise to ferromagnetic clusters coexisting with the antiferromagnetic component. Fil: Salcedo Rodriguez, Karen Lizeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina Fil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. CIC nanoGUNE Consolider; España. Instituto Nacional de Tecnología Industrial; Argentina Fil: RodrÍguez Torres, Claudia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina