Abstract
The magnetization direction in perpendicularly magnetized nonmagnet (NM)/ ferromagnetic-metal (FM)/oxide structurecan be efficiently controlled by in-plane current–induced spin-orbit torques (SOT). In the structure, in-plane current generates spin accumulation at the NM/FM interfaces via spin Hall effect and/or interfacial spin-orbit coupling, which gives rise to a torque to the FM layer. In this talk, we present the materials engineering which enhances the SOT switching efficiency in Pt/FM oxide structures. The first one is to control the resistivity of the Pt with varying the sputtering condition, which increases the spin Hall effect. The second is to engineer the NM/FM interface by introducing the thin Ti layers to modulate the interfacial spin-orbit coupling contribution. Moreover, we will also present a field-free SOT switching, which is achieved by replacing the NM layer with antiferromagnet IrMn, generating SOT as well as exchange bias effective in-plane magnetic field.

Bio
Dr Byong-Guk Park received his B. S. degree with Summa Cum Laude from the Department of Metallurgical Engineering, Hanyang University in 1997, and his graduate studies in the Department of Materials Science and Engineering, KAIST.The title of hisPh.D dissertation is “A study on magnetic tunnel junction with insulating barriers formed by ozone oxidation”.After finishinghis graduate studies, he spent three years as a post-doctoral researcher at Twente University in The Netherlands and five and half years as a research staff at the Hitachi Cambridge Laboratory, where he focused on the anisotropic magnetoresistance (AMR) effect in tunnel junctions and semiconductor spin transistors. In December 2011, he Joined the Department of Materials Science and Engineering, KAIST, as an assistant professor. He is currently a head of laboratory named “Nanospintronics Laboratory”, where he work on the utilization of spin-orbit coupling in various spintronic systems such as spin-orbit torques for efficient electrical manipulation of magnetization direction, the inverse spin Hall effect for conversion of spin current to charge voltage, spin Hall magnetoresistance, and spin Hall-induced dynamics of magnetic skyrmion, and development of antiferromagnetic spintronics.