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Thickness dependence of spin-orbit torques generated by WTe2

Cornell Affiliated Author(s)

Author

David MacNeill
Gregory Stiehl
Marcos Guimarães
Neal Reynolds
Robert Buhrman
Daniel Ralph

Abstract

We study current-induced torques in WTe2/permalloy bilayers as a function of WTe2 thickness. We measure the torques using both second-harmonic Hall and spin-torque ferromagnetic resonance techniques for samples with WTe2 thicknesses that span from 16 nm down to a single monolayer. We confirm the existence of an out-of-plane antidamping torque, and we show directly that the sign of this torque component is reversed across a monolayer step in the WTe2. The magnitude of the out-of-plane antidamping torque depends only weakly on WTe2 thickness, such that even a single-monolayer WTe2 device provides a strong torque that is comparable to much thicker samples. In contrast, the out-of-plane fieldlike torque has a significant dependence on the WTe2 thickness. We demonstrate that this fieldlike component originates predominantly from the Oersted field, thereby correcting a previous inference drawn by our group based on a more limited set of samples. © 2017 American Physical Society.

Date Published

Journal

American Physical Society (APS)

Volume

96

Issue

5

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029208030&doi=10.1103%2fPhysRevB.96.054450&partnerID=40&md5=c2de33f17a39ed05c5a7a295d74184b8

DOI

10.1103/PhysRevB.96.054450

Funding Source

DMR-1406333
ECCS-1542081
DMR-1120296
680-50-1311

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