Formation of guided spin-wave bullets in ferrimagnetic film stripes

TL;DR

This paper reports the experimental observation and numerical confirmation of guided spin-wave bullets in ferrimagnetic film stripes, revealing their stable, quasi-2D nonlinear propagation influenced by confinement, bridging 1D and 2D wave dynamics.

Contribution

It introduces the first experimental evidence of guided spin-wave bullets in ferrimagnetic stripes and analyzes their behavior through combined experimental and numerical methods.

Findings

Stable spin-wave packets are observed in ferrimagnetic stripes.

Shape and behavior of packets are strongly affected by confinement.

These modes are quasi-stable nonlinear solutions between 1D and 2D regimes.

Abstract

The formation of quasi-2D nonlinear spin-wave eigenmodes in longitudinally magnetized stripes of a ferrimagnetic film, so-called guided spin-wave bullets, was experimentally observed by using time- and space-resolved Brillouin light scattering spectroscopy and confirmed by numerical simulation. They represent stable spin-wave packets propagating along a waveguide structure, for which both transversal instability and interaction with the side edges of the waveguide are important. The experiments and the numerical simulation of the evolution of the spin-wave excitations show that the shape of the formed packets and their behavior are strongly influenced by the confinement conditions. The discovery of these modes demonstrates the existence of quasi-stable nonlinear solutions in the transition regime between one-dimensional and two-dimensional wave packet propagation.