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Separation of Artifacts from Spin‐Torque Ferromagnetic Resonance Measurements of Spin‐Orbit Torque for the Low‐Symmetry Van der Waals Semi‐Metal ZrTe <sub>3</sub>

Author

Thow Cham
Saba Karimeddiny
Vishakha Gupta
Joseph Mittelstaedt
Daniel Ralph

Abstract

Spin-orbit torques generated by exfoliated layers of the low-symmetry semi-metal ZrTe3 are measured using the spin-torque ferromagnetic resonance (ST-FMR) technique. When the ZrTe3 has a thickness greater than about 10 nm, artifacts due to spin pumping and/or resonant heating can cause the standard ST-FMR analysis to overestimate the true magnitude of the torque efficiency by as much as a factor of 30, and to indicate incorrectly that the spin-orbit torque depends strongly on the ZrTe3 layer thickness. Artifact-free measurements can still be achieved over a substantial thickness range by the method developed recently to detect ST-FMR signals in the Hall geometry as well as the longitudinal geometry. ZrTe3/Permalloy samples generate a conventional in-plane anti-damping spin torque efficiency (Formula presented.) = 0.014 ± 0.004, and an unconventional in-plane field-like torque efficiency (Formula presented.) = 0.003 ± 0.001. The out-of-plane anti-damping torque is negligible. It is suggested that artifacts similarly interfere with the standard ST-FMR analysis for other van der Waals samples thicker than about 10 nm. © 2021 Wiley-VCH GmbH

Date Published

Journal

Wiley

Volume

5

Issue

2

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85121392513&doi=10.1002%2fqute.202100111&partnerID=40&md5=3baee935c4169ecc2c06b9aa3814b266

DOI

10.1002/qute.202100111

Funding Source

FA9550‐19‐1‐0390
DMR‐1708499
DMR‐1719875
NNCI‐2025233
DE-SC0017671

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