# On anomalous temperature dependence of relaxation rate measured by \muSR in \alpha-YbAl_{0.986}Fe_{0.014}B_4

## TL;DR

This paper explains the anomalous temperature dependence of muon spin relaxation rate in Al_{0.986}Fe_{0.014}B_4 by proposing a Kondo effect mechanism involving local magnetic moments induced by conduction electron screening.

## Contribution

It introduces a semi-quantitative explanation for the anomalous relaxation rate using a Kondo effect model, challenging previous interpretations based solely on quantum critical valence transition.

## Key findings

- The anomalous temperature dependence can be explained by the Kondo effect.
- Local magnetic moments arise from conduction electron screening of the  ion.
- The proposed model aligns with observed non-Fermi liquid behaviors.

## Abstract

Recently, it was reported by MacLaughlin et al. in Phys. Rev. B 93, 214421 (2016) that \alpha-YbAl_{0.986}Fe_{0.014}B_4 exhibits an anomalous temperature dependence in the relaxation rate 1/T_{1} of $\mu$SR, and stressed that such temperature dependence cannot be understood by the scenario based on the quantum critical valence transition (QCVT) while this compound exhibits a series of the non-Fermi liquid behaviors explained by the theory of the QCVT. In this paper, we point out that the anomalous temperature dependence in 1/T_{1} can be understood semi-quantitatively by assuming that the attraction of a screening cloud of conduction electrons about the \mu^{+} induces a local magnetic moment arising from a 4f hole on the Yb ion, giving rise to the Kondo effect between heavy quasiparticles.