Imaging of transient magnetization dynamics of Co/Pt multilayer dots with X-ray magnetic circular dichroism excited by microwaves

Abstract

We investigated the magnetization dynamics of Co/Pt multilayer dots with diameters in the micron scale by X-ray magnetic circular dichroism (XMCD) with a focused beam with submicron dimensions. XMCD measurement with soft and hard X-rays revealed that the magnetic moments of Co and Pt strongly couple and precess with the same cone angle in ferromagnetic resonance conditions. The transient magnetization behavior of Co/Pt multilayer dots was investigated by pump–probe XMCD measurement with a scanning focused X-ray beam. A non-uniform magnetization distribution with concentric geometry including the phase of magnetization precession was visualized with excitation frequencies up to 3.05 GHz.