Azimuthal-spin-wave-mode-driven vortex-core reversals

作者：Yoo Myoung Woo; Kim Sang Koog^*

来源：Journal of Applied Physics, 2015, 117(2): 023904.

DOI：10.1063/1.4905689

We studied, by micromagnetic numerical calculations, asymmetric vortex-core reversals driven by the m = 1 and m = vertical bar 1 azimuthal spin-wave modes' excitations in soft magnetic circular nanodisks. We addressed the similarities and differences between the asymmetric core reversals in terms of the temporal evolutions of the correlated core-motion speed, locally concentrated perpendicular gyrofield, and magnetization dip near the original vortex core. The criterion for the core reversals was found to be the magnetization dip that must reach the out-of-plane magnetization component, mz = p, with the initial polarization p, where p = vertical bar(1) for the upward (downward) core magnetization. The core-motion speed and the associated perpendicular gyrofield, variable and controllable with static perpendicular field, H-z, applied perpendicularly to the disk plane, must reach their threshold values to meet the ultimate core-reversal criterion. Also, we determined the H-z strength and direction dependence of the core-switching time and threshold exciting field strength required for the core reversals, whose parameters are essential in the application aspect. This work offers deeper insights into the azimuthal spin-wave-driven core-reversal dynamics as well as an efficient means of controlling the azimuthal-modes-driven core reversals.

• 出版日期2015-1-14