Switching of perpendicular magnetization via orbital-current-induced torque from light metal Ru

R Rui Hou (Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, The Key Laboratory of Anti-inflammatory of Immune Medicines, Ministry of Education, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University) J Jiasen Cao (Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,) J Jinnan Liu Y Yaohui Du (Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,) B Bingyue Bian (Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,) W Wenjie Wu M Min Wang M Mengyang Yan (Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,) J Jia-Min Lai (Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,) X Xinlong Dong (School of Physics and Electronic Engineering, Shanxi Normal University 2 , Taiyuan 030031,) Z Zhengyu Xiao (State Key Laboratory for Spintronic Devices and Technologies 2 , Hangzhou 311300,) Y Yakun Liu D Delin Zhang Z Zhonghai Yu Z Zhiyong Quan F Fei Wang X Xiaohong Xu (Research Institute of Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education)

Abstract

Orbital torque (OT) harnesses orbital currents to electrically encode spin states, offering a promising route toward low-power spintronic devices. However, the microscopic mechanisms governing OT efficiency remain elusive. Here, we employ Ru, a light metal possessing positive spin and orbital Hall conductivities, as an orbital source to switch perpendicularly magnetized [Co/Pt]3 multilayers with a negative orbital-to-spin conversion coefficient. This configuration enables a clear separation between OT and conventional spin–orbit torque. We find that the OT efficiency decreases monotonically with increasing Ru thickness, confirming an interfacial rather than bulk origin of the orbital current. Notably, robust magnetization switching persists even for a Ru thickness of only 1 nm, achieving a critical switching current density of 1.9 × 107 A/cm2, nearly half that of the heavy-metal Pt reference. These findings not only elucidate the physical mechanism of OT but also establish key design principles for the development of energy-efficient orbitronic memory devices.

Article Details

Volume / Issue Vol. 128, Issue 7
Published February 16, 2026
ISSN 0003-6951
Publisher American Institute of Physics

Journal Info

Applied Physics Letters

American Institute of Physics

ISSN: 0003-6951 Physical Sciences

Authors (17)

R

Rui Hou

Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, The Key Laboratory of Anti-inflammatory of Immune Medicines, Ministry of Education, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University

J

Jiasen Cao

Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,

J

Jinnan Liu

Y

Yaohui Du

Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,

B

Bingyue Bian

Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,

W

Wenjie Wu

M

Min Wang

M

Mengyang Yan

Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,

J

Jia-Min Lai

Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering of Shanxi Normal University 1 , Taiyuan 030006,

X

Xinlong Dong

School of Physics and Electronic Engineering, Shanxi Normal University 2 , Taiyuan 030031,

Z

Zhengyu Xiao

State Key Laboratory for Spintronic Devices and Technologies 2 , Hangzhou 311300,

Y

Yakun Liu

D

Delin Zhang

Z

Zhonghai Yu

Z

Zhiyong Quan

F

Fei Wang

X

Xiaohong Xu

Research Institute of Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education