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arXiv · 2508.05968

Revisiting $\mu$SR Studies of Ion Dynamics in the Light of Extended Kubo-Toyabe Model

Takashi U. Ito·Ryosuke Kadono
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Abstract

The dynamical Kubo-Toyabe (dKT) function is extended to describe the spin relaxation under the coexisting dynamical and static internal magnetic fields. A detailed re-evaluation of the previous $\mu^\pm$SR data in Na$_x$CoO$_2$ using this function disfavors the conventional interpretation based on sodium-ion diffusion and instead supports the $\mu^+$ self-diffusion scenario. This also resolves the long-standing inconsistencies in the dKT-function-based $\mu$SR studies on ion diffusion from the viewpoint of classical over-barrier-jump mechanism.

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Takashi U. Ito, Ryosuke Kadono. 2025-08-08. Revisiting $\mu$SR Studies of Ion Dynamics in the Light of Extended Kubo-Toyabe Model. https://doi.org/10.1088/1742-6596%2F3222%2F1%2F012009

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