Field-free spin-orbit torque magnetization switching in a single-phase ferromagnetic and spin Hall oxide

Yongjoo Jo, Sanghyeon Kim, Eunjo Ryoo, Gahee Noh, Younji Kim, Gi-Jeong Han, Ji Hye Lee*, Won Joon Cho*, Gil-Ho Lee*, Si-Young Choi*, and Daesu Lee*
Nano Letters 24, 7100 (2024)
DOI: 10.1021/acs.nanolett.4c01788

Abstract

Current-induced spin−orbit torque (SOT) offers substantial promise forthe development of low-power, nonvolatile magnetic memory. Recently, a single phasematerial concurrently exhibiting magnetism and the spin Hall effect has emerged as ascientifically and technologically interesting platform for realizing efficient and compactSOT systems. Here, we demonstrate external-magnetic-field-free switching of perpendic-ular magnetization in a single-phase ferromagnetic and spin Hall oxide SrRuO3. Wedelicately altered the local lattices of the top and bottom surface layers of SrRuO3, whileretaining a quasi-homogeneous, single-crystalline nature of the SrRuO3 bulk. This leads tounbalanced spin Hall effects between the top and bottom layers, enabling net SOTperformance within single-layer ferromagnetic SrRuO3. Notably, our SrRuO3 exhibits thehighest SOT efficiency and lowest power consumption among all known single-layersystems under field-free conditions. Our method of artificially manipulating the localatomic structures will pave the way for advances in spin-orbitronics and the exploration ofnew SOT materials.