Collective modes in three-dimensional magnonic vortex crystals

Abstract

Collective modes in three-dimensional crystals of stacked permalloy disks with magnetic vortices are investigated by ferromagnetic resonance spectroscopy and scanning transmission X-ray microscopy. The size of the arrangements is increased step by step to identify the different contributions to the interaction between the vortices. These contributions are the key requirement to understand complex dynamics of three dimensional vortex crystals. Both vertical and horizontal coupling determine the collective modes. In-plane dipoles strongly influence the interaction between the disks in the stacks and lead to polarity-dependent resonance frequencies. Weaker contributions discern arrangements with different polarities and circularities that result from the lateral coupling of the stacks and the interaction of the core regions inside a stack. All three contributions are identified in the experiments and are explained in a rigid particle model.

Observation of asymmetric distributions of magnetic singularities across magnetic multilayers

“…films with magnetization quasiuniform along their thickness. In this paper, we have concentrated on the direction perpendicular to the interfaces since vertical coupling mechanisms are also fundamental for the design of three-dimensional (3D) magnetic devices [20][21][22]. As it will be described below, a strong asymmetry in the propagation of meronlike magnetic defects across a multilayer film was observed.…”

Spin Wave Excitations of the Interacting Two-Dimensional In-Plane Nano-Vortices

“…This lowest mode is reported to be of different kind, from an azimuthal mode of different order to localized or fundamental one [9][10][11]. Spin wave excitations are involved in the vortex core switching in an isolated dot [12] but above effects should be visible also in arrays of interacting vortices [13] and vortex crystals [14].…”

Second-order topological solitonic insulator in a breathing square lattice of magnetic vortices

“…We perform full micromagnetic simulations to verify theoretical predictions and find a good agreement between them. It is noted that the fabrication [57,58] and orbits tracking [59] of magnetic soliton lattice are all within the reach of current technology. Our findings open a new route toward realizing third-order TIs in classical magnetic systems that may inspire the design of robust spintronic devices in the future.…”