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arXiv · 1705.06328

Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator Cu$_2$OSeO$_3$

N. Prasai·B. A. Trump·G. G. Marcus·A. Akopyan·S. X. Huang·T. M. McQueen·J. L. Cohn
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Abstract

We report on the observation of magnon thermal conductivity $κ_m\sim$ 70 W/mK near 5 K in the helimagnetic insulator Cu$_2$OSeO$_3$, exceeding that measured in any other ferromagnet by almost two orders of magnitude. Ballistic, boundary-limited transport for both magnons and phonons is established below 1 K, and Poiseuille flow of magnons is proposed to explain a magnon mean-free path substantially exceeding the specimen width for the least defective specimens in the range 2 K $<T<$ 10 K. These observations establish Cu$_2$OSeO$_3$ as a model system for studying long-wavelength magnon dynamics.

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N. Prasai, B. A. Trump, G. G. Marcus, A. Akopyan, S. X. Huang, T. M. McQueen, J. L. Cohn. 2017-05-29. Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator Cu$_2$OSeO$_3$. https://doi.org/10.1103/physrevb.95.224407

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