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arXiv · 2609.39612

Anisotropic wavevector-dependent damping of thickness-quantized magnons

Tamara Azevedo·Rostyslav O. Serha·Yannik Kunz·Matthias R. Schweizer·Vitaliy I. Vasyuchka·Mathias Weiler·Andrii V. Chumak·Burkard Hillebrands·Mikhail Kostylev·Alexander A. Serga
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Abstract

Magnon damping is a key factor governing spin-wave transport and nonlinear dynamics of multimode magnon systems. However, many descriptions rely on the assumption of an effective mode-independent parameter, which can mask wavelength-dependent relaxation processes that depend on propagation geometry and mode profile. Here, we employ high-resolution parametric-instability spectroscopy to probe thickness-quantized spin waves with wavelengths down to about a hundred nanometers in micrometer-thick yttrium iron garnet films. The instability threshold exhibits a regular sawtooth dependence on the magnetic field, arising from switching between discrete thickness modes. Comparison with dipole--exchange theory reveals anisotropic wavevector-dependent damping that increases with mode number and depends differently on the in-plane and out-of-plane wavevector components.

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Tamara Azevedo, Rostyslav O. Serha, Yannik Kunz, Matthias R. Schweizer, Vitaliy I. Vasyuchka, Mathias Weiler, Andrii V. Chumak, Burkard Hillebrands, Mikhail Kostylev, Alexander A. Serga. 2026-09-30. Anisotropic wavevector-dependent damping of thickness-quantized magnons. https://arxiv.org/abs/2609.39612

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