Orbital Torque in Rare-Earth Transition-Metal Ferrimagnets

Fuente: arXiv
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Main Authors: Ding, Shilei, Kang, Min-Gu, Legrand, William, Gambardella, Pietro
Format: Preprint
Published: 2024
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author Ding, Shilei
Kang, Min-Gu
Legrand, William
Gambardella, Pietro
author_facet Ding, Shilei
Kang, Min-Gu
Legrand, William
Gambardella, Pietro
contents Orbital currents have recently emerged as a promising tool to achieve electrical control of the magnetization in thin-film ferromagnets. Efficient orbital-to-spin conversion is required in order to torque the magnetization. Here we show that the injection of an orbital current in a ferrimagnetic GdyCo100-y alloy generates strong orbital torques whose sign and magnitude can be tuned by changing the Gd content and temperature. The effective spin-orbital Hall angle reaches up to -0.25 in a GdyCo100-y/CuOx bilayer compared to +0.03 in Co/CuOx and +0.13 in GdyCo100-y/Pt. This behavior is attributed to the local orbital-to-spin conversion taking place at the Gd sites, which is about five times stronger and of the opposite sign relative to Co. Furthermore, we observe a manyfold increase in the net orbital torque at low temperature, which we attribute to the improved conversion efficiency following the magnetic ordering of the Gd and Co sublattices.
format Preprint
id arxiv_https___arxiv_org_abs_2406_19982
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Orbital Torque in Rare-Earth Transition-Metal Ferrimagnets
Ding, Shilei
Kang, Min-Gu
Legrand, William
Gambardella, Pietro
Materials Science
Orbital currents have recently emerged as a promising tool to achieve electrical control of the magnetization in thin-film ferromagnets. Efficient orbital-to-spin conversion is required in order to torque the magnetization. Here we show that the injection of an orbital current in a ferrimagnetic GdyCo100-y alloy generates strong orbital torques whose sign and magnitude can be tuned by changing the Gd content and temperature. The effective spin-orbital Hall angle reaches up to -0.25 in a GdyCo100-y/CuOx bilayer compared to +0.03 in Co/CuOx and +0.13 in GdyCo100-y/Pt. This behavior is attributed to the local orbital-to-spin conversion taking place at the Gd sites, which is about five times stronger and of the opposite sign relative to Co. Furthermore, we observe a manyfold increase in the net orbital torque at low temperature, which we attribute to the improved conversion efficiency following the magnetic ordering of the Gd and Co sublattices.
title Orbital Torque in Rare-Earth Transition-Metal Ferrimagnets
topic Materials Science
url https://arxiv.org/abs/2406.19982