ULTIMATE-I

The authors present a study of properties related to the magnetization reversal process in two thin film samples presenting magnetic stripe domains: Fe0.82Ga0.18 (Fe-Ga) and Ni0.81Fe0.19 (permalloy). In Fe-Ga thin films, they focus on the magnetization reversal driven by thermal activation, by considering the magnetic viscosity behavior. The results suggest that the reversal process occurs gradually, where the magnetization switches direction via ~10 nm-long jumps of the magnetic domain walls. On the other hand, vectorial hysteresis loops were performed in permalloy thin films with the aim of studying the behavior of the transverse magnetization component (perpendicular to the applied field) during the magnetization reversal process. They show that the measurement of the transversal magnetization component shows a much higher sensitivity for the determination of the in-plane magnetic anisotropy than the usual hysteresis loops where the magnetization is parallel to the applied field. Moreover, this allows them to highlight the competition between the intrinsic and rotatable anisotropies in thin film-present stripe domains.

P. Lopez Duque, D. Goijman, A. Sarmiento, G. Ramírez, L. Avilés-Félix, J. Gómez, M. Eddrief, A. Butera, P. Vavassori, and J. Milano, and D. Niebieskikwiat, Magnetization Reversal Phenomena in Thin Films Presenting Stripe Domains.

Available at SSRN: https://ssrn.com/abstract=4548057 or http://dx.doi.org/10.2139/ssrn.4548057

INMA Seminar: Ferromagnetic films on ferroelectric substrates – Alejandro Butera

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

The seminar took 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.

https://inma.unizar-csic.es/en/agenda-eventos/inma-seminar-alejandro-butera/

Iberian Thermoelectric Workshop – ITW ’23 Lisbon was hosted at Campus Tecnológico e Nuclear of IST-UL, Lisbon, from March 30-31 2023. The conference aims to provide opportunities to improve the collaboration between researchers and specialists in the thermoelectricity field and also allow an open discussion about the most recent advances in materials, properties measurement, module fabrication, and device applications.

Dra. Vanina Gisela Franco from Instituto de Física del Litoral IFIS-CONICET, Santa Fe, Argentina used her secondment to the University of Zaragoza to present her work on this exciting topic done in the scope of the ULTIMATE I project.

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.

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.

Pre-announcement
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