Double accumulation and anisotropic transport of magneto-elastic bosons in yttrium iron garnet films

Abstract

Interaction between quasiparticles of a different nature, such as magnons and phonons in a magnetic medium, leads to the mixing of their properties and the formation of hybrid states in the areas of intersection of individual spectral branches. We recently reported the discovery of a new phenomenon mediated by the magnon-phonon interaction: the spontaneous bottleneck accumulation of magneto-elastic bosons under electromagnetic pumping of pure magnons into a ferrimagnetic yttrium iron garnet film. Here, by studying the transport properties of the accumulated magneto-elastic bosons, we reveal that such accumulation occurs in two frequency-distant groups of quasiparticles: quasi-phonons and quasi-magnons. They propagate with different speeds in different directions relative to the magnetization field. The theoretical model we propose qualitatively describes the double accumulation effect, and the analysis of the two-dimensional spectrum of quasiparticles in the hybridization region allows us to determine the wavevectors and frequencies of each of the groups.

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Cited by in corpus (8)

• Roadmap on Spin-Wave Computing
• Spin and spin current -- From fundamentals to recent progress
• Correlation-enhanced interaction of a Bose-Einstein condensate with parametric magnon pairs and virtual magnons
• Composition-tunable magnon-polaron anomalies in spin Seebeck effects in epitaxial Bi${}_x$Y${}_{3-x}$Fe${}_5$O${}_{12}$ films
• Optimizing the magnon-phonon cooperativity in planar geometries
• Bose-Einstein condensation in systems with flux equilibrium
• Accumulation of magnetoelastic bosons in yttrium iron garnet: kinetic theory and wave vector resolved Brillouin light scattering
• Enhancement of magnon flux toward a Bose-Einstein condensate