The Bloch Point Pair-mediated Vortex Core Reversal.

Abstract

A lot of attention has been focused on the magnetic vortex structure [1,2] owing to its unique topological characteristics including high thermal stabilities as well as various dynamic modes such as gyration of vortex core (VC), radial and azimuthal spin wave modes [2-4]. In particular, the reversal of VC orientation is very interesting topological number through the vortex-antivortex pair creation and annihilation process [1,2]. During the reversal process, it has been known that a single point singularity, a Bloch point (BP), should be injected from the surface and it moves to the opposite surface [5]. In this work, we report a novel vortex core reversal mechanism - a BP pair-me-diated VC reversal by the resonant excitation of a three-dimensional spin-wave mode, an dsillation of the VC volume. Unlike the vortex-antivor-tex-pair-mediated mechanism [1,2], the BP pair is formed in the middle pf single VC structure, not surface during the reversal process as seen in. Fig.1. Our works provide a new method to realize ultrafast VC reversal, it helps to develop a spintronic device such as vortex-based memory devices.