Spin–orbit torque-induced magnetization switching in Pt/Co–Tb/Ta structures

Abstract

Although transition metal (TM)-rare earth (RE) alloy film has potential application as an information storage medium in spintronic devices, study of the physical mechanism and microscopic process for the current-induced magnetization switching by spin–orbit torque (SOT) in TM-RE is still inadequate. In this work, we investigated the SOT effect and its driven magnetization switching in Pt/Co–Tb/Ta structures with various Co–Tb compositions. The results show that the current-induced SOT effective fields follow 1/Ms law near the compensation composition in this structure. Because of the large SOT effective field and the low coercivity for the Co–Tb layer near the compensation composition, the current-induced magnetization switching with a threshold current density as low as 1010 A/m2 was achieved in the system. The direct Kerr imaging on the switching process verifies two different current-induced switching mechanisms in the Pt/Co–Tb/Ta system.

Determining spin-orbit torque in a single ferrimagnetic film without heavy metal via spin-torque ferromagnetic resonance

“…They prove that SOT (dampinglike and fieldlike effective field) diverges near T m . However, a high alternating current is required for the second harmonic Hall voltage, which oxidizes the RE Gd moment due to Joule heat to affect the analysis of the internal physical mechanism of SOT [16,17]. Compared to the second-harmonic techniques, spin-torque ferromagnetic resonance (ST FMR) is better for detecting SOT because a low microwave current is used.…”

Heat-Assisted Magnetization Switching in Flexible Spin–Orbit Torque Devices

“…Tremendous effort has been devoted to enhancing the charge-spin conversion efficiency in HM/FM bilayers, either by exploiting novel spin source materials with larger spin Hall angles or by modifying the HM/FM interface to enhance the spin transport efficiency. − Recently, different kinds of two-dimensional materials (MoS 2 , WTe 2 , Fe 3 GeTe 2 , and Fe 4 GeTe 2 ) and topological insulators (Bi 0.9 Sb 0.1 and Bi 2 Sb 3 ) have been investigated due to a larger spin Hall angle and potentially lower switching current density. However, the complex processing and preparation are not conducive to the massive production of SOT spintronic devices. ,− Moreover, voltage-controlled magnetic anisotropy (VCMA) has been proposed as an alternative approach to reducing the SOT switching current.…”