Hole doping effect on superconductivity in Ce(Co${}_{1\ensuremath{-}x}$Ru${}_{x}$)In${}_{5}$

Hole doping effect on superconductivity in Ce(Co $_{1 - x}$ Ru $_{x}$ )In $_{5}$

M. N. Ou, K. Gofryk, R. E. Baumbach, S. S. Stoyko, J. D. Thompson, J. M. Lawrence, E. D. Bauer, F. Ronning, A. Mar, and Y. Y. Chen

Phys. Rev. B 88, 195134 – Published 19 November 2013

Abstract

CeCoIn $_{5}$ , which has a superconducting transition temperature of 2.3 K, provides an excellent opportunity to study the interplay of superconductivity and magnetism near an antiferromagnetic quantum critical point. Previous studies have explored the effects of electron doping, magnetic field, and positive pressure on this system. To determine the effect of hole doping, we have grown single crystals of Ce(Co $_{1 - x}$ Ru $_{x}$ )In $_{5}$ in indium flux. The crystal structure of these Ru-doped samples was identified by powder XRD as the HoCoGa $_{5}$ -type. We find that the coherence temperature $T^{*}$ and the superconducting transition temperature $T_{c}$ decrease monotonically with increasing Ru content. Unlike the case of hole doping in CeCo(In $_{5 - x}$ Cd $_{x}$ ) alloys in which antiferromagnetism starts to emerge at $x = 0.025$ , we find no magnetic transition at our maximal nominal doping of $x_{nom} = 0.5$ , where $T_{c}$ is suppressed to 1.5 K. We discuss possible reasons for this difference between these two cases of hole doping.