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.
Fernando Fabris, Enio Lima Jr. (CNEA-CONICET), Jorge Martín Núñez (CNEA), Horacio E Troiani, Myriam H Aguirre (UniZar), Víctor Leborán, Francisco Rivadulla, Elin L. Winkler (CNEA-CONICET)
In magnetic tunnel junctions based on iron oxide nanoparticles, the disorder and the oxidation state of the surface spin as well as the nanoparticles functionalization play a crucial role in the magnetotransport properties. We report a systematic study of the effects of vacuum annealing on the structural, magnetic, and transport properties of self-assembled ∼10 nm Fe3O4 nanoparticles. This work shows new insights into the influence of the nanoparticle interfacial composition, as well as their spatial arrangement, on the tunnel transport of self-assemblies, and evidence of the importance of optimizing the nanostructure fabrication for increasing the tunneling current without degrading the spin-polarized current.
Dr. Jose Santiso (ICN2), Dr. Carlos García (USM), Dr. Cristian Romanque (USM), Dr. Loïc Henry, Dr. Nicolas Bernier, Dr. Núria Bagués, Dr. José Manuel Caicedo (ICN2), Dr. Manuel Valvidares, Dr. Felip Sandiumenge
Nanoscale epitaxial yttrium iron garnet films still pose fundamental issues regarding their interfacial behavior and impact on magnetic properties. This work shows interfacial yttrium accumulation forming octahedral antisite defects. The resulting suppression of magnetic moment from the minority sublattice results in an increased saturation magnetization. These results suggest a strong impact of unbalanced interdiffusion on magnetic behavior.
JEMS 2023, 27th Aug. to 1st Sep. 2023, Madrid (Spain)
Luis Avilés (CNEA): « Spin transport and magnetic dynamics in ultra low damping epitaxial Co100-xFex/Ta bilayers »; authors: D. Velázquez Rodríguez, J.E. Gómez, T.E. Torres, M.H. Aguirre J. Milano, P. Costanzo, L. Avilés-Félix, A. Butera
Lara Solís (CNEA): « Temperature-dependence of ferromagnetic resonance in YIG garnets thin films »; authors: Lara M. Solís, Santiago Carreira, Javier Briático, Abdelmadjid Anane, Myriam H. Aguirre, Laura Steren
Myriam Aguirre (UNIZAR): « Synthesis of magnetite from natural pyrite for energy conversion devices »; authors: Vanina G. Franco, Adriana E. Candia, Jorge M. Núñez, Miguel Rengifo, Myriam H. Aguirre
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.
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.
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.
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 (firstname.lastname@example.org) and Dr. Myriam H. Aguirre (email@example.com).
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