paper

Bulk superconductivity and Pauli paramagnetism in nearly stoichiometric CuCo $_{2}$ S $_{4}$

arXiv:2107.09848 · doi:10.1103/PhysRevMaterials.5.074804

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 $a = 9.454$ Ã , 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 Ã , 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.

8 pages, 6 figures

Bulk superconductivity and Pauli paramagnetism in nearly stoichiometric CuCo2​S4​

Abstract

Bulk superconductivity and Pauli paramagnetism in nearly stoichiometric CuCo $_{2}$ S $_{4}$