Authors:	Kim, Jun-young Cramer, Joel Lee, Kyujoon Han, Dong-Soo Go, Dongwook Salev, Pavel Lapa, Pavel N. Vargas, Nicolas M. Schuller, Ivan K. Mokrousov, Yuriy Jakob, Gerhard Kläui, Mathias
Title:	Tuning spin-orbit torques across the phase transition in VO2/NiFe heterostructure
Online publication date:	1-Aug-2022
Year of first publication:	2022
Language:	english
Abstract:	The emergence of spin-orbit torques as a promising approach to energy-efficient magnetic switching has generated large interest in material systems with easily and fully tunable spin-orbit torques. Here, current-induced spin-orbit torques in VO2/NiFe heterostructures are investigated using spin-torque ferromagnetic resonance, where the VO2 layer undergoes a prominent insulator-metal transition. A roughly twofold increase in the Gilbert damping parameter, alpha, with temperature is attributed to the change in the VO2/NiFe interface spin absorption across the VO2 phase transition. More remarkably, a large modulation (+/- 100%) and a sign change of the current-induced spin-orbit torque across the VO2 phase transition suggest two competing spin-orbit torque generating mechanisms. The bulk spin Hall effect in metallic VO2, corroborated by the first-principles calculation of the spin Hall conductivity sigma SH approximate to-104PLANCK CONSTANT OVER TWO PIe omega-1 m-1, is verified as the main source of the spin-orbit torque in the metallic phase. The self-induced/anomalous torque in NiFe, with opposite sign and a similar magnitude to the bulk spin Hall effect in metallic VO2, can be the other competing mechanism that dominates as temperature decreases. For applications, the strong tunability of the torque strength and direction opens a new route to tailor spin-orbit torques of materials that undergo phase transitions for new device functionalities.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-7331
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Advanced functional materials 32 17
Pages or article number:	2111555
Publisher:	Wiley-VCH
Publisher place:	Weinheim
Issue date:	2022
ISSN:	1616-301X
Publisher DOI:	10.1002/adfm.202111555
Appears in collections:	DFG-491381577-H