Quantum criticality and development of antiferromagnetic order in the quasikagome Kondo latticeCeRh1−xPdxSn

Abstract

CeRhSn with a quasikagome lattice of Ce atoms in the hexagonal $c$ plane has been expected to be in close vicinity to a zero-field quantum criticality derived from magnetic frustration. We have studied how the ground state changes with substitution of Pd for Rh in $\mathrm{CeR}{\mathrm{h}}_{1\ensuremath{-}x}\mathrm{P}{\mathrm{d}}_{x}\mathrm{Sn}$ $(x\ensuremath{\le}0.75)$ by measuring the specific heat $C$, magnetic susceptibilities ${\ensuremath{\chi}}_{\mathrm{dc}}$ and ${\ensuremath{\chi}}_{\mathrm{ac}}$, magnetization $M$, electrical resistivity \ensuremath{\rho}, and magnetoresistance. For $x=0$, the field dependence of ${\ensuremath{\chi}}_{\mathrm{ac}}$ at $T=0.03\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ shows a peak at $B\ensuremath{\parallel}a=3.5\phantom{\rule{0.16em}{0ex}}\mathrm{T}$, confirming the spin-flop crossover in the field applied along the hard axis. The temperature dependence of ${\ensuremath{\chi}}_{\mathrm{ac}}$ shows a broad maximum at 0.1 K whereas $C/T$ continues to increase down to 0.08 K. For $x\ensuremath{\geqq}0.1,\ensuremath{\rho}(T)$ is dominated by incoherent Kondo scattering and both $C/T$ and ${\ensuremath{\chi}}_{\mathrm{ac}}(T)$ exhibit peaks, indicating the development of an antiferromagnetic order. The ordering temperature rises to 2.5 K as $x$ is increased to 0.75. Our results indicate that the ground state in the quasikagome Kondo lattice $\mathrm{CeR}{\mathrm{h}}_{1\ensuremath{-}x}\mathrm{P}{\mathrm{d}}_{x}\mathrm{Sn}$ leaves the quantum critical point at $x=0$ with increasing $x$ as a consequence of suppression of both the magnetic frustration and Kondo effect.