Magnon spin transport driven by the magnon chemical potential in a magnetic insulator

Ludo J. Cornelissen, Kevin J. H. Peters, Rembert A. Duine, Gerrit E. W. Bauer, Bart J. van Wees

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Abstract

We develop a linear-response transport theory of diffusive spin and heat transport by magnons in magnetic insulators with metallic contacts. The magnons are described by a position dependent temperature and chemical potential that are governed by diffusion equations with characteristic relaxation lengths. Proceeding from a linearized Boltzmann equation, we derive expressions for length scales and transport coefficients. For yttrium iron garnet (YIG) at room temperature we find that long-range transport is dominated by the magnon chemical potential. We compare the model's results with recent experiments on YIG with Pt contacts [L.J. Cornelissen, et al., Nat. Phys. 11, 1022 (2015)] and extract a magnon spin conductivity of $\sigma_{m}=5\times10^{5}$ S/m. Our results for the spin Seebeck coefficient in YIG agree with published experiments. We conclude that the magnon chemical potential is an essential ingredient for energy and spin transport in magnetic insulators.
Original languageUndefined/Unknown
Article number014412
Pages (from-to)1-16
JournalPhysical Review B
Volume94
DOIs
Publication statusPublished - 13 Apr 2016

Keywords

  • cond-mat.mes-hall

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