Direct observation of Oersted-field-induced magnetization dynamics in magnetic nanowires
Résumé
We have used time-resolved x-ray photoemission electron microscopy to investigate the magnetization dynamics induced by nanosecond current pulses in NiFe/Cu/Co nanowires. The Oersted magnetic field present during the current pulses induces a large tilt of the NiFe magnetization, transverse to the wires. Spin-wave-like oscillations of the NiFe magnetization are also observed and attributed to precessional motion about the effective field. Our results clearly show that both the quasi-static and dynamic effects of the Oersted field have to be taken into account when interpreting current-induced domain wall motion in multilayered nanowires. This internal, transverse magnetic field may contribute to the increased efficiency of current-induced domain wall motion observed in NiFe/Cu/Co nanowires.
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