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.