Bulk superconductivity and Pauli paramagnetism in nearly stoichiometric CuCo${}_2$S${}_4$

Abstract

It has long remained elusive whether CuCo${}_2$S${}_4$ thiospinel shows bulk superconductivity. Here we clarify the issue by studying on the samples of sulfur-deficient CuCo${}_2$S${}_{3.7}$ and sulfurized CuCo${}_2$S${}_4$. The sample CuCo${}_2$S${}_{3.7}$ has a smaller lattice constant of $a=9.454$ Å, and it is not superconducting down to 1.8 K. After a full sulfurization, the $a$ axis of the thiospinel phase increases to 9.475 Å, and the thiospinel becomes nearly stoichiometric CuCo${}_2$S${}_4$, although a secondary phase of slightly Cu-doped CoS${}_2$ forms. Bulk superconductivity at 4.2 K and Pauli paramagnetism have been demonstrated for the sulfurized CuCo${}_2$S${}_4$ by the measurements of electrical resistivity, magnetic susceptibility, and specific heat.

arXiv comment8 pages, 6 figures

References in corpus (6)

• Elaboration of the alpha-Model Derived from the BCS Theory of Superconductivity
• Superconducting materials classes: introduction and overview
• Superconductivity in the Cu(Ir1-xPtx)2Se4 Spinel
• Predicting Unconventional High Temperature Superconductors in Trigonal Bipyramidal Coordinations
• Effect of impurity scattering on superconductivity in K${}_2$Cr${}_3$As${}_3$
• Unconventional High Temperature Superconductivity in Cubic Zinc-blende Transition Metal Compounds

Cited by in corpus (2)

• Superconductivity with the enhanced upper critical field in the Pt-Doping CuRh2Se4 spinel
• Experimental electronic phase diagram in a diamond-lattice antiferromagnetic system