Investigation of superconducting and normal-state properties of the filled-skutterudite system PrPt4Ge12−xSbx

Abstract

We report a study of the superconducting and normal-state properties of the filled-skutterudite system PrPt4Ge12−xSbx. Polycrystalline samples with Sb concentrations up to x=5 were synthesized and investigated by means of x-ray diffraction, electrical resistivity, magnetic susceptibility, and specific heat measurements. We observed a suppression of superconductivity with increasing Sb substitution up to x=4, above which no signature of superconductivity was observed down to 140 mK. The Sommerfeld coefficient, γ, of superconducting specimens decreases with increasing x up to x=3, suggesting that superconductivity may depend on the density of electronic states in this system. The specific heat for x=0.5 exhibits an exponential temperature dependence in the superconducting state, reminiscent of a nodeless superconducting energy gap. We observed evidence for a weak “rattling” mode associated with the Pr ions, characterized by an Einstein temperature ΘE∼60 K for 0≤x≤5; however, the rattling mode may not play any role in suppressing superconductivity.

Source-reported materials — not catalogue approval

Similar papers