Spin orientations and spin-orbit torque in magnetic nanostructures

Abstract

In this thesis three different spintronic devices and their static behaviours are studied under external magnetic field or applied current. We started to work on the static properties of magnetic antivortices, formed in a special geometry called astroid, and achieved stable antivortex nucleation, annihilation and manipulation. We also observed the response of antivortex to the external magnetic field. Another study was the observation of magnetic radial vortices in the presence of interfacial Dzyaloshinskii-Moriya interaction (i-DMI) in Pt/CoFeB/Ti nanopillar multilayers. By tuning the magnetic anisotropy via interface engineering and postpro duction treatments, we achieved to stabilize a variety of magnetic configurations such as Ńeel skyrmions, horseshoes and radial vortices at room temperature and under zero bias field. Lastly, we have focused on the observation of self-torque of (100) oriented IrMn3 antiferromagnet. We observed the exchange field shift with respect to applied current. Additionally, we studied the effect of spin orbit torque by measuring DC current de pendence of Hall bar resistance. The efficiency of different types of heavy metals, which have different spin Hall angles, was studied to compare their resistance variation of the device.