Ferromagnetic films on ferroelectric substrates seminar by Alejandro Butera (CONICET)

INMA Seminar: Ferromagnetic films on ferroelectric substrates – Alejandro Butera

The INMA Seminar and RISE-ULTIMATE-I Project are happy to announce a seminar entitled « Ferromagnetic films on ferroelectric substrates ». The seminar will take place on 17 April 2023. The session will be given by the CONICET professor and researcher Alejandro Butera, from the Instituto Balseiro de San Carlos de Bariloche-Argentina.

The seminar will take place on Monday 17 April at 12h in the Aula del Edificio I+D+I, 1st floor, Campus Río Ebro.

Summary: We present a study of the effects of applying an electric field on the magnetic response of Fe89Ga11 thin films deposited on PMN-PT (011) and (001) single-crystal ferroelectric substrates. Upon application of an electric field, we have observed that the M vs.H hysteresis loops are modified in the films grown on PMN-PT (011) crystals, consistent with a positive magnetostriction constant that depends on the film thickness. From ferromagnetic resonance experiments at 9.5 GHz, we obtained a thickness-dependent magnetoelectric constant in substrates (011), with a maximum dH/dE ~150 Oe.m/MV for t = 28 nm, consistent with estimates made from M vs. H loops.

We find that the facile magnetisation direction can be rotated by 90° with the application of an electric field only for 28 nm films deposited on PMN-PT (011). In thinner films, the magnetoelectric coefficient is too small to overcome the magnetic anisotropy. These results indicate that if magnetostrictive materials are to be applied in straintronics devices, the dependence of magnetic parameters on film thickness must be taken into account for optimal performance.

I will also give a summary of other topics we are investigating in the Magnetic Films group of the Magnetic Resonance Division – Bariloche, Argentina.

Authors: María Julia Jiménez, Livio Leiva, J.L. Ampuero Torres, G. Cabeza, J.E. Gómez, D. Velázquez Rodriguez, J. Milano, and A. Butera (presenter) from Laboratory of Magnetic Resonance Imaging, Bariloche Atomic Centre and Balseiro Institute, Bariloche, Argentina.


Alejandro Butera from CNEA Magnetic Resonance Laboratory secondment to the University of Zaragoza

Alejandro Butera, CONICET professor and researcher of CNEA Magnetic Resonance Laboratory, from the Instituto Balseiro de San Carlos de Bariloche-Argentina is visiting the Advanced Microscopy Laboratory (LMA) of the University of Zaragoza-Spain (UNIZAR) and Aragón Materials Science Institute (ICMA).

During his stay, he will study FeCo and permalloy samples prepared by focused ion beam (FIB) and use transmission electron microscope (TEM) analysis by Titan TEM.

Alejandro Butera and Teobaldo Torres are in pictures preparing to enter the Clean Room for using the Dual Beam 650 and lamellae preparation.

Secondment to Senzor Infiz and participation at the annual conference of the German Physical Society

ULTIMATE-I secondment to Senzor Infiz of Sindy J. Rodríguez Sotelo (Instituto de Física del Litoral IFIS-CONICET, Santa Fe, Argentina).

The secondment was used to explore interactions directing the self-assembly of magnetic nanocubes and prepare the publication with Carlos Garcia (CCTVal, Universidad Técnica Federico Santa María, Valparaíso, Chile). Also, a prolonged stay in Senzor Infiz was used to discuss the modelling of production processes, particularly the exfoliation of two-dimensional materials.

The results of the secondment are presented at the German Physical Society annual conference from 26 March to 31 March 2023 on the campus of the Technical University Dresden. The conference was organized by the Condensed Matter Section of the society.

Magnetic Nanodevices for Spintronic And Neuromorphic Applications (OFFER, PhD position)

Project description:
Magnetic nanodevices display a wide variety of behaviours that resemble the properties of both neurons and synapses. Neuromorphic computing takes inspiration from the way the brain processes data to improve energy efficiency and computational power. For the development of these magnetic nanodevices, including spin-orbit torque memories (SOT-MRAM), magnetic SOT oscillators and resistance-switching-based memories, optimization of materials and interfaces is required. The project involves the fabrication and characterization of magnonic and spintronic heterostructures for application in magnetic nanodevices.

From the point of view of materials science, basic studies of materials in large facilities will be carried out and from the applied point of view, systems with optimized properties of resistivity, generation/detection of spin currents and SOT efficiency will be worked on.

Deadline (reception of applications): April 15, 2023

Applicants should submit a CV, a list of publications, and a list of possible references to Dr. M. A. Laguna Marco (anlaguna@unizar.es) and Dr. Myriam H. Aguirre (maguirre@unizar.es).

Main Tasks:

  • Synthesis and optimization of thin-film nanomaterials. Manufacture of devices by lithography in a clean room: magnetic and electrical memories, oscillators.
  • Conducting experiments on novel quantum materials
  • Structural characterization (performing XRR, XRD, and TEM Microscopy experiments), electrical and magnetic characterization.
  • Electrical and thermomagnetic transport measurements.
  • Analysis of data.
  • Preparation of reports and scientific articles and presentation of results at scientific conferences

    Qualifications/Skills: Applicants should have a Master in Physics, Materials Science, Chemistry, Eng. or related fields. Priority will be given to candidates with a demonstrated background in standard fabrication techniques, and characterization of magnetic/spintronic materials.

    The candidate should have excellent written and oral communication skills in English.

Research Profile: PhD student
Research Field: Magnetic Nanodevices for Spintronic And
Neuromorphic Applications
Location: Zaragoza (Spain)

Time of Contract: 2 (CSIC) + 2 (University of Zaragoza) years

Argentinian ULTIMATE-I researchers win projects for spintronics research

ULTIMATE-I researchers from Argentina, Luis Avilé and Julian Milano from CNEA / @Resonanlab / Instituto Balseiro, Bariloche win Argentinian national PICT projects in #spintronics and magnetic materials.

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!

Looking forward to the results of these projects!

Juan Carlos Rojas-Sanchez receives an ERC Consolidator grant for his work in spintronics

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.

Original in French: https://factuel.univ-lorraine.fr/node/22436

A seminar entitled « Strain effects in vanadium dioxide films with metal-insulator electronic transition »

Friday, December 16, at 11 a.m. Buenos Aires Time, Prof. Dr José Santiso gave a seminar entitled « Strain effects in vanadium dioxide films with the metal-insulator electronic transition » at « Laboratorio de Física de Superficies e Interfaces », Instituto de Física del Litoral (IFIS-Litoral, CONICET-UNL).

José Santiso is a researcher at the Catalan Institute of Nanoscience and Nanotechnology (ICN2) in Barcelona, Spain. Dr Santiso, invited by Dr Mario C. G. Passeggih is part of the ULTIMATE-I (Ultra Thin Magneto Thermal Sensoring) project supported by the European Union.

The following is a brief summary.

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.[1] 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 [2], 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.

[1] 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.

[2] F. Sandiumenge, L. Rodríguez, M. Pruneda, C. Magén, J. Santiso, G. Catalan, Metallic Diluted Dimerization in VO2 Tweeds, Adv. Mater. 33 (2021) 2004374.

Presentation of new results in magnetism at Simposio Chileno de Fisica

ULTIMATE-I members from Chile, Serbia, and Spain participated and presented their new results on magnetism and spintronics during the annual conference of the Chilean Physical Society held at Universidad Técnica Federico Santa María (USM), Valparaíso, Chile.

Paolo Vavassori from nanoGune in Spain gave a talk on Ultrafast control of magnetization by light.

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).

Secondment to Magnetic Resonance Laboratory

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.