Spin-Wave Emission from Vortex Cores under Static Magnetic Bias Fields

• DOI: 10.1021/acs.nanolett.0c03740
• Publication Date: 2021-02-06T16:46:39Z
• Authors: Sina Mayr; Lukáš Flajšman; Simone Finizio; Aleš Hrabec; Markus Weigand; Johannes Förster; Hermann Stoll; Laura J. Heyderman; Michal Urbánek; Sebastian Wintz; Jörg Raabe
• Keywords: Spin wave; Magnetostatics; Permalloy; Micromagnetics

We studied the influence of a static in-plane magnetic field on alternating-field-driven emission nanoscale spin waves from vortex cores. Time-resolved scanning transmission X-ray microscopy was used to image in disk structures synthetic ferrimagnets and single ferromagnetic layers. For both systems, it found that an increasing bias continuously displaces wave-emitting core center toward its edge without noticeably altering spin-wave dispersion relation. In case single-layer disk, anisotropic lateral expansion occurs at higher fields, which leads directional rather than radial-isotropic propagation waves. Micromagnetic simulations confirm these findings further show focusing effects occur such depending shape controlled by field.