Low-temperature anomalies in magnetic, transport, and thermal properties of single-crystal CeRhSn with valence fluctuations

Abstract

Magnetic, transport, thermal, and crystallographic properties are reported for single crystals of CeRhSn crystallizing in the hexagonal ZrNiAl-type structure. We found high anisotropy in both electrical resistivity $({\ensuremath{\rho}}_{a}\ensuremath{\approx}5{\ensuremath{\rho}}_{c}$ at 70 K) and magnetic susceptibility $({\ensuremath{\chi}}_{c}\ensuremath{\approx}10{\ensuremath{\chi}}_{a}$ at 0.4 K), which is atypical for a valence-fluctuating Ce compound. At low temperatures, $\ensuremath{\rho}(T)$ and $\ensuremath{\chi}(T)$ show power-law behaviors; ${\ensuremath{\rho}}_{a}(T)\ensuremath{\propto}{T}^{1.5}$ and ${\ensuremath{\rho}}_{c}(T)\ensuremath{\propto}T,$ and ${\ensuremath{\chi}}_{a}\ensuremath{\propto}{T}^{\ensuremath{-}0.35}$ and ${\ensuremath{\chi}}_{c}\ensuremath{\propto}{T}^{\ensuremath{-}1.1}$ down to 0.4 K. These behaviors and the rather large residual resistivity were not affected by long-term annealing. On cooling from 7 K to 0.5 K, the specific heat divided by temperature $C/T$ increased as $\ensuremath{-}\mathrm{ln}T$ and saturated to a rather large value of $0.2{\mathrm{J}/\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{}\mathrm{K}}^{2}.$ These experimental results are discussed in relation to the possible atomic disorder.