R&D: Multilevel States Driven by Spin-Orbit Torque in P-Composition Graded (Ga,Mn)(As,P) Film

AIP Advances has published an article written by Kyung Jae Lee, Kyoul Han, Sanghoon Lee, Physics Department, Korea University, Seoul 136-701, Republic of Korea, Xinyu Liu, M. Dobrowolska, and Jacek K. Furdyna, Department of Physics and Astronomy, University of Notre Dame, Notre Dame, Indiana 46556, USA.

Abstract: “We have studied spin-orbit torque (SOT) magnetization switching in a (Ga,Mn)(As,P) film with vertically-graded magnetic anisotropy. The magnetization switching chirality during current scans reveals that strain-induced Dresselhaus-type spin-orbit field does the major role for spin polarization of carriers causing SOT in the system. The volume fraction of SOT magnetization switching significantly depends on the magnitude and direction of the applied bias field. This feature leads to the realization of stable multilevel magnetic states in composition-graded (Ga,Mn)(As,P) film. The experiment demonstrates that multiple magnetic state can be robustly set by using appropriate bias fields. This characteristic can be used to realize SOT-driven multi-state memories and/or memristor devices, which are key ingredients for neuromorphic computing.“