Generalized Two-Temperature Model for Coupled Phonon-Magnon Diffusion
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Magnon_Cooling_v6_revised_2.pdf
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1.39 MB
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Author(s)
Liao, Bolin
Zhou, Jiawei
Chen, Gang
Date Issued
July 2014
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Liao, Bolin, Jiawei Zhou, and Gang Chen. “Generalized Two-Temperature Model for Coupled Phonon-Magnon Diffusion.” Physical Review Letters 113, no. 2 (July 2014).
Version
Author's final manuscript
Abstract
We generalize the two-temperature model [Sanders and Walton, Phys. Rev. B 15, 1489 (1977)] for coupled phonon-magnon diffusion to include the effect of the concurrent magnetization flow, with a particular emphasis on the thermal consequence of the magnon flow driven by a nonuniform magnetic field. Working within the framework of the Boltzmann transport equation, we derive the constitutive equations for coupled phonon-magnon transport driven by gradients of both temperature and external magnetic fields, and the corresponding conservation laws. Our equations reduce to the original Sanders-Walton two-temperature model under a uniform external field, but predict a new magnon cooling effect driven by a nonuniform magnetic field in a homogeneous single-domain ferromagnet. We estimate the magnitude of the cooling effect in an yttrium iron garnet, and show it is within current experimental reach. With properly optimized materials, the predicted cooling effect can potentially supplement the conventional magnetocaloric effect in cryogenic applications in the future.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.113.025902
