Anomalous temperature dependence of the relaxation rate measured by muon spin rotation in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{YbAl}}_{0.986}{\mathrm{Fe}}_{0.014}{\mathrm{B}}_{4}$

Anomalous temperature dependence of the relaxation rate measured by muon spin rotation in $α − {YbAl}_{0.986} {Fe}_{0.014} B_{4}$

Kazumasa Miyake and Shinji Watanabe

Phys. Rev. B 98, 075125 – Published 14 August 2018

Abstract

Recently, it was reported by MacLaughlin et al. in Phys. Rev. B 93, 214421 (2016) that $α − {YbAl}_{0.986} {Fe}_{0.014} B_{4}$ exhibits an anomalous temperature dependence in the relaxation rate $1 / T_{1}$ of $μ SR$ , 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 semiquantitatively by assuming that the attraction of a screening cloud of conduction electrons about the $μ^{+}$ induces a local magnetic moment arising from a $4 f$ hole on the Yb ion, giving rise to the Kondo effect between heavy quasiparticles.