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arXiv · 2105.13943

Anisotropic Magnon Spin Transport in Ultra-thin Spinel Ferrite Thin Films -- Evidence for Anisotropy in Exchange Stiffness

Ruofan Li·Peng Li·Di Yi·Lauren Riddiford·Yahong Chai·Yuri Suzuki·Daniel C. Ralph·Tianxiang Nan
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Abstract

We report measurements of magnon spin transport in a spinel ferrite, magnesium aluminum ferrite $\mathrm{MgAl_{0.5}Fe_{1.5}O_4}$ (MAFO), which has a substantial in-plane four-fold magnetic anisotropy. We observe spin diffusion lengths $> 0.8$ $\mathrm{μm}$ at room temperature in 6 nm films, with spin diffusion length 30% longer along the easy axes compared to the hard axes. The sign of this difference is opposite to the effects just of anisotropy in the magnetic energy for a uniform magnetic state. We suggest instead that accounting for anisotropy in exchange stiffness is necessary to explain these results.

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Ruofan Li, Peng Li, Di Yi, Lauren Riddiford, Yahong Chai, Yuri Suzuki, Daniel C. Ralph, Tianxiang Nan. 2021-05-28. Anisotropic Magnon Spin Transport in Ultra-thin Spinel Ferrite Thin Films -- Evidence for Anisotropy in Exchange Stiffness. https://doi.org/10.1021/acs.nanolett.1c04332

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