Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 19: Spin Dynamics / Spin Torque I

MA 19.6: Vortrag

Mittwoch, 27. Februar 2008, 15:15–15:30, EB 301

Real-time soft X-ray microscopy of current-induced domain-wall oscillations — •Lars Bocklage¹, René Eiselt¹, Markus Bolte¹, Benjamin Krüger², Peter Fischer³, Ulrich Merkt¹, and Guido Meier¹ — ¹Institut für Angewandte Physik, Universität Hamburg — ²I. Institut für Theoretische Physik, Universität Hamburg — ³Center for X-Ray Optics, LBNL, USA

Novel concepts for high density and ultrafast magnetic storage devices suggest domain walls (DW) or vortices in nanostructures to store information. Spin-polarized currents exerting a torque on the local magnetization can move these magnetization configurations [1,2]. Magnetic soft X-ray microscopy allows to image changes in the DW structures upon spin current injection with a spatial resolution down to 15 nm [3]. Spin dynamics can be imaged by a stroboscopic pump-probe measurement scheme at a temporal resolution below 100 ps. We have prepared vortex DWs in a restoring potential in permalloy nanostructures and displaced the vortex from its equilibrium position by injecting nanosecond current pulses. The displacement holds while the pulse is applied, afterwards the DW starts a free oscillation with strong damping. The frequency, the damping constant, and the confining potential of our samples is calculated within a harmonic oscillator model.
This work was supported by the DPG via SFB 668 and GRK 1286 as well as by the DOE via Contract No. DE-AC02-05-CH11231.
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