Tuning Spin-Orbit Torques Across the Phase Transition in VO2/NiFe Heterostructure

Kim JY, Cramer J, Lee K, Han DS, Go D, Salev P, Lapa PN, Vargas NM, Schuller IK, Mokrousov Y, Jakob G, Klaeui M (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Advanced Functional Materials Wiley-VCH Verlag

Book Volume: 32

Article Number: 2111555

Journal Issue: 17

DOI: 10.1002/adfm.202111555

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, α, 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 (Formula presented.), 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.

Involved external institutions

Johannes Gutenberg-Universität Mainz (JGU)

Germany (DE) University of California, San Diego

United States (USA) (US)

How to cite

APA:

Kim, J.-Y., Cramer, J., Lee, K., Han, D.-S., Go, D., Salev, P.,... Klaeui, M. (2022). Tuning Spin-Orbit Torques Across the Phase Transition in VO2/NiFe Heterostructure. Advanced Functional Materials, 32(17). https://doi.org/10.1002/adfm.202111555

MLA:

Kim, Jun-Young, et al. "Tuning Spin-Orbit Torques Across the Phase Transition in VO2/NiFe Heterostructure." Advanced Functional Materials 32.17 (2022).

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