Microscopic Understanding of Thermal-magnon Transport in Low-damping Ferrimagnetic Thin Films
Abstract
Thermally generated magnons enable heat-driven spin transport in magnetic insulators, yet the relative importance of multiple microscopic mechanisms governing their propagation remains incompletely understood. Here, we investigate thermal magnon transport in low-damping Li0.5Al1.0Fe1.5O4/Pt nanodevices using a nonlocal spin Seebeck geometry that separates magnon transport from local thermoelectric effects. Thermal imaging establishes a detector region outside the thermal healing length, enabling intrinsic nonlocal measurements. We find that thermal magnon transport is strongly suppressed by magnetic fields far above saturation, and further that thermal magnon transport decreases with increasing temperature despite an increasing magnon population. Brillouin light scattering reveals the key microscopic mechanism driving this effect: increasing field reduces the group velocity of backward volume magnons, directly reducing the magnon spin diffusion length. Micromagnetic simulations reproduce this behavior only when a temperature-dependent exchange stiffness is included. These results identify magnon group velocity and exchange stiffness as key parameters governing thermal magnon transport in ferrimagnetic thin films.
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BibTeX
@misc{takana2026microscopic,
title = {{Microscopic Understanding of Thermal-magnon Transport in Low-damping Ferrimagnetic Thin Films}},
author = {Lerato Takana and Katya Mikhailova and Junwei Tong and Xiangcheng Liu and Kwangyul Hu and Juan Hofer and Guanxiong Qu and Clare Yu and Ivan Schuller and Michael Flatté and Xiaoqin Li and Yuri Suzuki},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.09674},
eprint = {2609.09674},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.09674},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Microscopic Understanding of Thermal-magnon Transport in Low-damping Ferrimagnetic Thin Films
AU - Lerato Takana
AU - Katya Mikhailova
AU - Junwei Tong
AU - Xiangcheng Liu
AU - Kwangyul Hu
AU - Juan Hofer
AU - Guanxiong Qu
AU - Clare Yu
AU - Ivan Schuller
AU - Michael Flatté
AU - Xiaoqin Li
AU - Yuri Suzuki
PY - 2026
DA - 2026/09/26
PB - arXiv
DO - 10.48550/arxiv.2609.09674
UR - https://arxiv.org/abs/2609.09674
AB - Thermally generated magnons enable heat-driven spin transport in magnetic insulators, yet the relative importance of multiple microscopic mechanisms governing their propagation remains incompletely understood. Here, we investigate thermal magnon transport in low-damping Li_0.5Al_1.0Fe_1.5O_4/Pt nanodevices using a nonlocal spin Seebeck geometry that separates magnon transport from local thermoelectric effects. Thermal imaging establishes a detector region outside the thermal healing length, enabling intrinsic nonlocal measurements. We find that thermal magnon transport is strongly suppressed by magnetic fields far above saturation, and further that thermal magnon transport decreases with increasing temperature despite an increasing magnon population. Brillouin light scattering reveals the key microscopic mechanism driving this effect: increasing field reduces the group velocity of backward volume magnons, directly reducing the magnon spin diffusion length. Micromagnetic simulations reproduce this behavior only when a temperature-dependent exchange stiffness is included. These results identify magnon group velocity and exchange stiffness as key parameters governing thermal magnon transport in ferrimagnetic thin films.
ER -