Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 17: Spin Dynamics / Spin Torque II

MA 17.1: Invited Talk

Wednesday, March 24, 2010, 14:00–14:30, H10

Current-induced magnetization dynamics — •Mathias Kläui — Fachbereich Physik, Universität Konstanz, 78457 Konstanz

When combining transport with magnetic materials on the nanoscale, a range of exciting and novel phenomena emerge. While magneto-resistance effects have been widely studied, the reciprocal spin transfer torque effect that leads to current-induced domain wall motion, has become the focus of intense research in the last few years [1]. In current-induced domain wall motion (CIDM), due to a spin torque effect, electrons transfer angular momentum and thereby push a domain wall with velocities > 100m/s. We have comprehensively investigated this effect using magnetotransport and dynamic imaging techniques based on synchrotron light sources and we have observed that this interaction is strongly dependent on the wall spin structure [2-4]. To understand the underlying mechanisms, we have separated the effects of the adiabatic and non-adiabatic spin torque terms from parasitic Oersted field effects and we have developed a robust measure of the non-adiabaticity parameter. Dynamic imaging shows that AC currents can excite non-linear domain wall oscillations and we determine the oscillatory eigenmodes and quantitatively map the asymmetric and even non-linear potential, which can be engineered by applying external fields [5]. [1] M. Kläui, Topical Review in J. Phys: Condens. Matter 20, 313001 (2008);[2] M. Kläui et al., PRL 94, 106601 (2005), PRL 95, 26601 (2005);[3] O. Boulle et al., PRL 101, 216601 (2008);[4] L. Heyne et al., PRL 100, 66603 (2008);[5] D. Bedau et al., PRL 99, 146601 (2007); PRL 101, 256602 (2008)