Role of dimensional crossover on spin-orbit torque efficiency in magnetic insulator thin films

Qiming Shao; Chi Tang; Guoqiang Yu; Aryan Navabi; Hao Wu; Congli He; Junxue Li; Pramey Upadhyaya; Peng Zhang; Seyed Armin Razavi; Qing Lin He; Yawen Liu; Pei Yang; Se Kwon Kim; Cheng Zheng; Yizhou Liu; Lei Pan; Roger K Lake; Xiufeng Han; Yaroslav Tserkovnyak; Jing Shi; Kang L Wang

doi:10.1038/s41467-018-06059-7

Role of dimensional crossover on spin-orbit torque efficiency in magnetic insulator thin films

Nat Commun. 2018 Sep 6;9(1):3612. doi: 10.1038/s41467-018-06059-7.

Authors

Qiming Shao¹, Chi Tang², Guoqiang Yu^{3

4}, Aryan Navabi¹, Hao Wu⁵, Congli He¹, Junxue Li², Pramey Upadhyaya⁶, Peng Zhang¹, Seyed Armin Razavi¹, Qing Lin He¹, Yawen Liu², Pei Yang^{1

7}, Se Kwon Kim⁶, Cheng Zheng¹, Yizhou Liu⁸, Lei Pan¹, Roger K Lake⁸, Xiufeng Han⁵, Yaroslav Tserkovnyak⁶, Jing Shi², Kang L Wang^{9

10}

Affiliations

¹ Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA.
² Department of Physics & Astronomy, University of California, Riverside, CA, 92521, USA.
³ Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA. [email protected].
⁴ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China. [email protected].
⁵ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
⁶ Department of Physics & Astronomy, University of California, Los Angeles, CA, 90095, USA.
⁷ York-Nanjing Joint Center for Spintronics and Nano Engineering (YNJC), School of Electronics Science and Engineering, Nanjing University, Nanjing, 210093, China.
⁸ Department of Electrical and Computer Engineering, University of California, Riverside, CA, 92521, USA.
⁹ Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA. [email protected].
¹⁰ Department of Physics & Astronomy, University of California, Los Angeles, CA, 90095, USA. [email protected].

Abstract

Magnetic insulators (MIs) attract tremendous interest for spintronic applications due to low Gilbert damping and the absence of Ohmic loss. Spin-orbit torques (SOTs) on MIs are more intriguing than magnetic metals since SOTs cannot be transferred to MIs through direct injection of electron spins. Understanding of SOTs on MIs remains elusive, especially how SOTs scale with the MI film thickness. Here, we observe the critical role of dimensionality on the SOT efficiency by studying the MI layer thickness-dependent SOT efficiency in tungsten/thulium iron garnet (W/TmIG) bilayers. We show that the TmIG thin film evolves from two-dimensional to three-dimensional magnetic phase transitions as the thickness increases. We report the significant enhancement of the measured SOT efficiency as the TmIG thickness increases, which is attributed to the increase of the magnetic moment density. We demonstrate the current-induced SOT switching in the W/TmIG bilayers with a TmIG thickness up to 15 nm.

Publication types

Research Support, Non-U.S. Gov't