Nonlocal magnon-polaron transport in yttrium iron garnet

L. J. Cornelissen, K. Oyanagi, T. Kikkawa, Z. Qiu, T. Kuschel, G. E.W. Bauer, B. J. Van Wees, E. Saitoh

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28 Citations (Scopus)

Abstract

The spin Seebeck effect (SSE) is observed in magnetic insulator|heavy metal bilayers as an inverse spin Hall effect voltage under a temperature gradient. The SSE can be detected nonlocally as well, viz. in terms of the voltage in a second metallic contact (detector) on the magnetic film, spatially separated from the first contact that is used to apply the temperature bias (injector). Magnon-polarons are hybridized lattice and spin waves in magnetic materials, generated by the magnetoelastic interaction. Kikkawa et al. [Phys. Rev. Lett. 117, 207203 (2016)] interpreted a resonant enhancement of the local SSE in yttrium iron garnet (YIG) as a function of the magnetic field in terms of magnon-polaron formation. Here we report the observation of magnon-polarons in nonlocal magnon spin injection/detection devices for various injector-detector spacings and sample temperatures. Unexpectedly, we find that the magnon-polaron resonances can suppress rather than enhance the nonlocal SSE. Using finite element modeling, we explain our observations as a competition between the SSE and spin diffusion in YIG. These results give unprecedented insights into the magnon-phonon interaction in a keymagnetic material.

Original languageEnglish
Article number104441
JournalPhysical Review B
Volume96
Issue number10
DOIs
Publication statusPublished - 2017
Externally publishedYes

Keywords

  • Magnetoelastic effect
  • Magnons
  • Seebeck effect
  • Spintronics
  • PhononsSpin

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    Cornelissen, L. J., Oyanagi, K., Kikkawa, T., Qiu, Z., Kuschel, T., Bauer, G. E. W., Van Wees, B. J., & Saitoh, E. (2017). Nonlocal magnon-polaron transport in yttrium iron garnet. Physical Review B, 96(10), [104441]. https://doi.org/10.1103/PhysRevB.96.104441