Abstract
Spin-wave-mediated vortex core reversal is investigated using x-ray magnetic circular dichroism in a time-resolved scanning transmission x-ray microscope in combination with micromagnetic simulations. The evolution of magnetization dynamics in Permalloy disks is imaged after excitation with one-period rotating rf-field bursts. Selective unidirectional switching of the vortex polarity is achieved ...
Abstract
Spin-wave-mediated vortex core reversal is investigated using x-ray magnetic circular dichroism in a time-resolved scanning transmission x-ray microscope in combination with micromagnetic simulations. The evolution of magnetization dynamics in Permalloy disks is imaged after excitation with one-period rotating rf-field bursts. Selective unidirectional switching of the vortex polarity is achieved due to different switching thresholds for clockwise and counterclockwise excitations. A lower limit of about 200 ps for the unidirectional switching time after the onset of a one-period burst is found for the geometry of our disks (1.6 mu m in diameter and 50 nm in thickness).
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