Document Type

Article

Department or Administrative Unit

Physics

Publication Date

3-7-2016

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.

Comments

This article was originally published in Physical Review B. The full-text article from the publisher can be found here.

Journal

Physical Review B

Rights

© 2016 American Physical Society

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