paper

Superconductivity in the Correlated Pyrochlore Cd_2Re_2O_7

arXiv:cond-mat/0107309 · doi:10.1103/PhysRevB.64.180503

Abstract

We report the observation of superconductivity in high-quality CdReO single crystals with room-temperature pyrochlore structure. Resistivity and ac susceptibility measurements establish an onset transition temperature T = 1.47 K with transition width T = 0.25 K. In applied magnetic field, the resistive transition shows a type-II character, with an approximately linear temperature-dependence of the upper critical field H. The bulk nature of the superconductivity is confirmed by the specific heat jump with C = 37.9 mJ/mol-K. Using the value extracted from normal-state specific heat data, we obtain C/T = 1.29, close to the weak coupling BCS value. In the normal state, a negative Hall coefficient below 100 K suggests electron-like conduction in this material. The resistivity exhibits a quadratic T-dependence between 2 and 60 K, i.e., +AT, indicative of Fermi-liquid behavior. The values of the Kadowaki-Woods ratio A/ and the Wilson ratio are comparable to that for strongly correlated materials.

4 pages, 5 figures

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