VISUALIZATION OF CURRENT INDUCED SPIN ACCUMULATIONS IN THE STRONG SPIN-ORBITAL COUPLING MATERIALS

Abstract

Charge-to-spin conversion in various material systems is the key to understanding a variety of spin-orbitronics phenomena. In this thesis, we first image the current induced spin accumulation at the channel edges of Bi2Se3 and BiSbTeSe2 topological insulators as well as Pt heavy metal by scanning photovoltage microscopy at room temperature. The spin polarization is along the out-of-plane direction with opposite signs for the two channel edges. The spin lifetime and spin Hall angle can be estimated using this technique. We further study the facet-dependent current induced spin accumulation in (001)- and (111)-oriented IrMn3. We observe a significant out-of-plane spin accumulation on the device surface in (001)-oriented IrMn3. We finally show the current induced magnetization switching in the IrMn/CoTb system. Our results pave the way for a better understanding of the current induced spin accumulations in various materials as well as the interaction between charge, spin, and light.