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Symmetry Control of Unconventional Spin–Orbit Torques in IrO2

Cornell Affiliated Author(s)

Author

Michael Patton
Gautam Gurung
Ding-Fu Shao
Gahee Noh
Joseph Mittelstaedt
Marcel Mazur
Jong-Woo Kim
Philip Ryan
Evgeny Tsymbal
Si-Young Choi
Daniel Ralph
Mark Rzchowski
Tianxiang Nan
Chang-Beom Eom

Abstract

Abstract Spin?orbit torques generated by a spin current are key to magnetic switching in spintronic applications. The polarization of the spin current dictates the direction of switching required for energy-efficient devices. Conventionally, the polarizations of these spin currents are restricted to be along a certain direction due to the symmetry of the material allowing only for efficient in-plane magnetic switching. Unconventional spin?orbit torques arising from novel spin current polarizations, however, have the potential to switch other magnetization orientations such as perpendicular magnetic anisotropy, which is desired for higher density spintronic-based memory devices. Here, it is demonstrated that low crystalline symmetry is not required for unconventional spin?orbit torques and can be generated in a nonmagnetic high symmetry material, iridium dioxide (IrO2), using epitaxial design. It is shown that by reducing the relative crystalline symmetry with respect to the growth direction large unconventional spin currents can be generated and hence spin?orbit torques. Furthermore, the spin polarizations detected in (001), (110), and (111) oriented IrO2 thin films are compared to show which crystal symmetries restrict unconventional spin transport. Understanding and tuning unconventional spin transport generation in high symmetry materials can provide a new route towards energy-efficient magnetic switching in spintronic devices.

Date Published

Journal

Advanced Materials

Volume

35

Issue

39

Number of Pages

2301608+

ISBN Number

0935-9648

URL

https://doi.org/10.1002/adma.202301608

DOI

https://doi.org/10.1002/adma.202301608

Funding Source

ONR N00014-20-1-2844
DMR-1720415
GBMF9065
DE-FG02-06ER46327
DE-SC0017671
OIA-2044049
2020R1A4A1018935

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