Mathias Kläui

Title

Spin Current-induced Magnetization Dynamics

Abstract

When combining transport with magnetic materials on the nanoscale, a range of exciting and novel phenomena emerge. The magnetization configuration influences strongly the transport due to spin-dependent scattering (e.g. Giant Magnetoresistance, Nobel Prize 2007). Conversely the reciprocal effect of the spin polarized currents acting on the magnetization also exists. This “spin transfer torque” effect leads to current-induced domain wall motion, which has become the focus of intense research in the last few years due to a strong interest in the fundamental interaction between spin – polarized currents and the magnetization and possible applications in logic and data storage. We use high resolution magnetic imaging and magnetotransport to comprehensively investigate current-induced magnetization dynamics due to the spin transfer torque effect. We directly determine the acting torque terms and find that the effect strongly depends on the spin structure opening a way to tailor the interaction. In a next step we generate pure diffusive spin currents with no associated net charge current. By separating charge and spin transport we find large efficiencies for domain wall displacement due to strong spin accumulation absorption resulting from pure spin currents.