Nonlinear emission of spin-wave caustics from an edge mode of a micro-structured Co2Mn0.6Fe0.4Si waveguide

TL;DR

This paper demonstrates nonlinear spin-wave emission from an edge mode in a low-damping Heusler waveguide, revealing caustic beam formation at harmonic frequencies due to anisotropic dispersion.

Contribution

It reports the first observation of nonlinear higher harmonic generation and caustic spin-wave emission from an edge mode in a Heusler waveguide, supported by analytical modeling.

Findings

Observation of caustic spin-wave beams at harmonic frequencies

Edge mode as the source of nonlinear harmonic generation

Analytical description based on anisotropic dispersion

Abstract

Magnetic Heusler materials with very low Gilbert damping are expected to show novel magnonic transport phenomena. We report nonlinear generation of higher harmonics leading to the emission of caustic spin-wave beams in a low-damping, micro-structured Co2Mn0.6Fe0.4Si Heusler waveguide. The source for the higher harmonic generation is a localized edge mode formed by the strongly inhomogeneous field distribution at the edges of the spin-wave waveguide. The radiation characteristics of the propagating caustic waves observed at twice and three times the excitation frequency are described by an analytical calculation based on the anisotropic dispersion of spin waves in a magnetic thin film.