We report electrical resistivity, magnetization, and specific heat measurements on the correlated electron system ${\mathrm{Ce}}_{1-x}{\mathrm{Sm}}_x{\mathrm{CoIn}}_5$ ($0\le x\le 1$). Superconductivity (SC) in the heavy-fermion compound ${\mathrm{CeCoIn}}_5$, which is suppressed with increasing Sm concentration $x$, and antiferromagnetic (AFM) order of ${\mathrm{SmCoIn}}_5$, which is suppressed with decreasing $x$, converge near a quantum critical point at $x_{\mathrm{QCP}}\approx 0.15$, with no indication of coexistence of SC and AFM in the vicinity of the QCP. Non-Fermi-liquid (NFL) behavior is observed in the normal-state electrical resistivity, $\rho \left(T\right)$, and specific heat, $C\left(T\right)$, in the vicinity of the QCP; e.g., the coefficient and the exponent of the power-law $T$ dependence of $\rho \left(T\right)$ exhibit pronounced maxima and minima, respectively, at $x_{\mathrm{QCP}}$, while $C\left(T\right)/T$ exhibits a logarithmic divergence in $T$ at $x_{\mathrm{QCP}}$. A low-temperature upturn in $\rho \left(T\right)$ develops in the range $0.70\le x\le 0.85$ which is reminiscent of a single impurity Kondo effect, suggesting that Sm substitution tunes the relative strength of competing Kondo and Ruderman-Kittel-Kasuya-Yosida energy scales. The suppression of SC with increasing $x$ is probably associated with the exchange interaction between the Ce quasiparticles involved in the superconductivity and the magnetic moments of the Sm ions.

• Received 16 April 2018
• Revised 18 June 2018

DOI:https://doi.org/10.1103/PhysRevB.97.235149