Two projects are funded by the Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación.
The topics of the projects are Spin Dynamics in Micro- and Nanostructures (Luis Avilé) and Control of acoustic and spin wave propagation through ferromagnetic thin films with periodic domain patterns (Julian Milano).
The goal of the projects is to investigate the spin transport phenomena in magnetic micro- and nanostructures for the generation, detection and control of spin currents!
Manipulating the magnetization of materials on extremely short time scales, in the picosecond range, is a highly coveted grail for information technologies. The complex magneto-optical techniques currently used are difficult to integrate spintronics into devices. To overcome these constraints, Juan Carlos Rojas-Sanchez of the Institut Jean Lamour (CNRS/Université de Lorraine) and one of the PIs of the ULTIMATE-I project has received an ERC Consolidator grant for his Magnetallien project.
In spintronics, components are controlled by a quantum parameter of electrons: the spin. This approach promises much more powerful and energy-efficient integrated circuits and components but faces many technical challenges.
« To achieve this goal, I am interested in materials where there is a strong coupling between spin and orbit, » explains Juan Carlos Rojas-Sanchez, a CNRS researcher at the Institut Jean Lamour (CNRS/Université de Lorraine). For example, when an electric current is passed through a platinum nanowire, it scatters the electrons in opposite directions according to their spin orientation, creating a spin current that can be injected into an adjacent magnetic layer. This phenomenon has applications such as memories, sensors or the realization of logic circuits.
Different approaches are envisaged to study and control this key ingredient: the spin-orbit coupling. For example, by generating a spin current in a thin layer of magnetic material and injecting it into a neighbouring layer. Understanding and exploiting this phenomenon on the picosecond time scale remains a challenge. It is currently only possible to obtain a signal of up to a hundred gigahertz using lasers and particularly « heavy » optical means, » notes Juan Carlos Rojas-Sanchez. I want to reduce the cost and size of the devices by exploiting new physical systems that use spin-orbit interaction.
To this end, he has set up the MAGNETALLIEN project, for which he has just been awarded this ERC Consolidator grant.
Vanadium dioxide (VO2)is an archetypical material showing a metal-insulator (M-I) Mott transition at about T=68C with several orders of magnitude change in the resistivity between the semiconducting low-T M1 phase and the high-T metallic rutile R phase. It has been proposed as a good candidate directly for Resistive-Random Access Memory (RRAM) devices or as complementary selector in combination of a bipolar RRAM device because of its high on/off ratio, fast switching speed and high current density. Although in bulk form the transition is above room temperature either chemical doping or mechanical strain have been demonstrated to bring the transition closer or even below room temperature making it very attractive in different devices. This work studies the structure features across transition of high quality strained epitaxial VO2 films deposited on isostructural rutile TiO2 (001) single crystals. Since M-I transition in VO2 is accompanied by a structural change between monoclinic M1 phase and tetragonal R phase, with substantial variation in cell parameters, the nucleation of the high-T R phase embedded in the low-T M1 phase during transition, is expected to generate local interfacial regions with a large strain. The characterization of the structural features of the films by means of synchrotron X-ray Diffraction upon thermal cycles revealed the formation of local strain effects during the phase transition in competition with the epitaxial strain induced by the growth on the mismatched TiO2 substrates. Such interphase regions between M1 and R crystal domains are submitted to a uniaxial strain (overlapped to the biaxial in-plane epitaxial strain) that stabilizes other polytypic VO2 insulating phases (monoclinic M2, and triclinic transitional M3 or T phase) beyond their expected stability regions. Concomitant to the subtle structural distortions a slight rotation of the monoclinic crystal domains occurs to accommodate the elastic energy constraints. The persistence of the coexistence of those polytypic phases even at room temperature turns VO2 into a complex heterogeneous material. Nonetheless, at conditions where XRD of the films seems to indicate a pure rutile R phase, HRTEM analysis revealed a certain degree of heterogeneity at the nanoscale forming an intricate tweed pattern of other polytypes with different arrangements of V-V dimers along the c-axis direction , still displaying a metallic character. Altogether these observations evidence that VO2 micro and nanostructure, and therefore its electrical response, depends on a subtle balance of unconventional strain relaxation mechanisms.
 L. Rodríguez, F. Sandiumenge, C. Frontera, J.M. Caicedo, J. Padilla, G. Catalán, J. Santiso, Strong strain gradients and phase coexistence at the metal-insulator transition in VO2 epitaxial films, Acta Mater. 220 (2021) 117336.
 F. Sandiumenge, L. Rodríguez, M. Pruneda, C. Magén, J. Santiso, G. Catalan, Metallic Diluted Dimerization in VO2 Tweeds, Adv. Mater. 33 (2021) 2004374.
Mario Mery, Claudio Gonzalez, J. E. Valdés, Vanina Franco, Myriam H. Aguirre, and Carlos Garcia presented a poster on the Ferromagnetic response of NiO irradiated with H2 and He+ ion beams. Their work included research performed by three project partner organizations (CONICET from Argentina, UNIZAR from Spain, and USM from Chile).
ULTIMATE-I secondment to Centro Atómico Bariloche’s Magnetic Resonance Laboratory: Héloïse Damas, Juan-Carlos Rojas-Sánchez (both IJL/UL/CNRS – France), Igor Stanković (IPB/SenzorInfiz – Serbia), and Paolo Vavassori (CIC nanoGUNE – Spain).
A high level of interaction during the secondment provides us with a productive period regarding knowledge transfer, scientific idea exchange and discussion.
L. B. Steren, INN-Conicet, Argentina, Control of magnetism by electric fields and strains in oxide-based multiferroics. J. Curiale, Instituto de Nanociencia y Nanotecnología, CNEA– CONICET, Río Negro, Argentina, Universal critical exponents of the magnetic domain wall depinning transition. Andrew D. Kent, Center for Quantum Phenomena, Dept. of Physics, New York University, USA, Spin-orbit Torques in Antiferromagnet Insulator/Heavy Metal Heterostructures. P. Vavassori, CIC nanoGUNE BRTA, Spain, Plasmon-assisted nanomagnetic logics.
J. E. Gómez, Centro Atómico Bariloche, CNEA, INN, CONICET, Argentine, Tungsten crystal structure: Its role on the spin transport parameters. H. Damas, Université de Lorraine, CNRS, France, Currentinduced Self-Torque in GdFeCo ferrimagnet. I. Stanković, Scientific Computing Laboratory, University of Belgrade, Serbia, Tubular structures of magnetic particles – an accessible platform for curvilinear nanomagnetism. M.A. Laguna–Marco. Instituto de Nanociencia y Materiales de Aragón, Zaragoza, Spain, Optimizating the performance of IrO2 by doping: Ir1–xMxO2 thin films (M = Sn, Cr, Co).
International Workshop on Spintronics – Spin Argentina 2022 started today.
Between November 7 and 11, around 125 participants from different parts of the world will enjoy in 36 invited talks, 24 contributed, 56 posters, and between presenters four 2022 IEEE Magnetic Society Distinguished Lecturers.
The participants will exchange their latest results and ideas about #magnetism, #magnetic materials and their applications! In these 4 weeks of classes and experiments, they will explore different aspects of magnetism and spintronics.
The Workshop includes two networking activities: Meet the experts on Monday at 8:30 pm at a location to be defined, and Women in Magnetism on Tuesday at 8 pm at the same hotel as the conference.
Meet the experts provides PhD students and PostDocs with an opportunity to participate in a small-group discussion and get advice on career planning, technical paper writing, publication, job searches, research opportunities, or societal involvement. NETWORKING ACTIVITIES sponsored by the IEEE Magnetics Society Initiative to “Promote Magnetism in LATAM”.
Women in Magnetism event will propose a discussion about motivation programs for girls/young students in different countries The discussed topics will be: (1) the motivation of young female students for STEM careers (from primary school to university), and (2) Gender equality and science: from laws to social and work visibility.
This Spin Argentina event is possible thanks to the « historical » support of Gen Tatara, which has been joined this year by IEEE Magnetic Society and IOP Publishing Latinoamerica, CONICET, INN, CNEA, Fundación Balsiero, Instituto Balseiro, and MINCYT. The school is actively supported by the Ultra-Thin Magneto Thermal-SensorIng (ULTIMATE-I) project of the European Commission and in particular its participating organizations French Centre National de la Recherche Scientifique (CNRS), and the University of Zaragoza (UNIZAR), coordinator.
This Spin Argentina event is possible thanks to the « historical » support of Gen Tatara, which has been joined this year by our project Ultimate-I (Ultra Thin Magneto Thermal Sensoring supported by the European Union), and the IEEE Magnetic Society, as well as IOP Publishing Latinoamerica, CONICET, INN, CNEA, Fundación Balsiero, Instituto Balseiro, and MINCYT.
This has allowed us to keep costs to a minimum and to be able to give about 30 waivers to students and young post-docs from different parts of the world. More recently, thanks to the IEEE initiative to Promote Magnetism in LATAM, we can support partially covering travel and accommodation expenses for LATAM students. And to organize networking activities.
We have two networking activities: Meet the experts on Monday at 8:30 pm at a location to be defined, and Women in Magnetism on Tuesday at 8 pm at the same hotel as the conference. Everyone is invited to participate. More details of these events will be shared later and will also be posted on the website.
Between October 17 and 28, the « V School of Nanoscience and Nanotechnology » takes place, organized at the Institute of Nanoscience and Nanotechnology (CONICET-CNEA) / the Constituyentes Atomic Center (San Martín, Buenos Aires Province). This year, the School is focused on the growth and characterization of nanomaterials in the form of thin films. The school is supported by the Ultra-Thin Magneto Thermal-SensorIng (ULTIMATE-I) project of the European Commission, French Centre National de la Recherche Scientifique (CNRS), and the University of Zaragoza (UNIZAR).
Nanoscience and nanotechnology are advancing rapidly, forming a disciplinary area with a deep impact both at the level of basic and applied science, providing solutions for the main problems facing humanity, such as the generation, conversion and storage of energy, the caring for the environment, the diagnosis and treatment of diseases or the storage and processing of information. The School of Nanoscience and Nanotechnology (ENN) will contribute to the education or training of new generations of scientists and technologists in the different manufacturing techniques, characterization, assembly and control of nanosystems, as well as the different calculation tools. The activity is aimed at doctoral and post-doctoral students and young researchers interested in nanoscience and nanotechnology and in the development of nanomaterials and devices. This opportunity will allow ULTIMATE-I researchers to present tutorials on thin film growth, nanocharacterization by XRD and TEM, device nanofabrication, nanomagnetism, and transport measurements.
The school is aimed at doctoral students, post-doctoral students and young researchers interested in the area of nanoscience and nanotechnology.
The classes will be given by project members Laura Steren (CONICET), Myriam Aguirre (UNIZAR), Javier Briático (CNRS), Juan Bonaparte (CNEA) and Diego Rubí (CONICET):