Nature Communications (Apr 2023)

A puzzling insensitivity of magnon spin diffusion to the presence of 180-degree domain walls

  • Ruofan Li,
  • Lauren J. Riddiford,
  • Yahong Chai,
  • Minyi Dai,
  • Hai Zhong,
  • Bo Li,
  • Peng Li,
  • Di Yi,
  • Yuejie Zhang,
  • David A. Broadway,
  • Adrien E. E. Dubois,
  • Patrick Maletinsky,
  • Jiamian Hu,
  • Yuri Suzuki,
  • Daniel C. Ralph,
  • Tianxiang Nan

DOI
https://doi.org/10.1038/s41467-023-38095-3
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 7

Abstract

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Abstract We present room-temperature measurements of magnon spin diffusion in epitaxial ferrimagnetic insulator MgAl0.5Fe1.5O4 (MAFO) thin films near zero applied magnetic field where the sample forms a multi-domain state. Due to a weak uniaxial magnetic anisotropy, the domains are separated primarily by 180° domain walls. We find, surprisingly, that the presence of the domain walls has very little effect on the spin diffusion – nonlocal spin transport signals in the multi-domain state retain at least 95% of the maximum signal strength measured for the spatially-uniform magnetic state, over distances at least five times the typical domain size. This result is in conflict with simple models of interactions between magnons and static domain walls, which predict that the spin polarization carried by the magnons reverses upon passage through a 180° domain wall.