The Superconductivity of Some Transition Metal Compounds

TLDR

The study examined most known transition‑metal boride, carbide, nitride, oxide, silicide, and germanide compounds that had not previously been magnetically tested for superconductivity, including the first germanide superconductors V₃Ge and Mo₃Ge. Eighty such compounds were screened for superconductivity down to 1.20 K using a magnetic susceptibility method. Eleven new superconductors were identified, with transition temperatures ranging from 1.30 K to 17.1 K, and V₃Si exhibited the highest Tc (17.1 K) among binary superconductors.

Abstract

About eighty transition metal compounds comprising borides, carbides, nitrides, oxides, silicides, and germanides of metals of Groups 4A, 5A, and 6A were tested for superconductivity down to 1.20\ifmmode^\circ\else\textdegree\fi{}K, using a magnetic method. Among the specimens were most of the known compounds of the above type not examined magnetically for superconducting behavior by previous workers, and in all cases the structures were checked by x-ray diffraction analysis. The following eleven new superconductors were discovered, with the transition temperatures (\ifmmode^\circ\else\textdegree\fi{}K) shown in parentheses: ${\mathrm{W}}_{2}$B (3.10\ifmmode^\circ\else\textdegree\fi{}), ${\mathrm{Nb}}_{2}$C (9.18\ifmmode^\circ\else\textdegree\fi{}), ${\mathrm{Ta}}_{2}$C (3.26\ifmmode^\circ\else\textdegree\fi{}), ${\mathrm{Nb}}_{4}$${\mathrm{N}}_{3}$ (7.2\ifmmode^\circ\else\textdegree\fi{}), ${\mathrm{V}}_{3}$Si (17.1\ifmmode^\circ\else\textdegree\fi{}), ${\mathrm{V}}_{3}$Ge (6.01\ifmmode^\circ\else\textdegree\fi{}), ${\mathrm{Mo}}_{3}$Si (1.30\ifmmode^\circ\else\textdegree\fi{}), ${\mathrm{Mo}}_{3}$Ge (1.43\ifmmode^\circ\else\textdegree\fi{}), $\ensuremath{\alpha}$-Th${\mathrm{Si}}_{2}$ (3.16\ifmmode^\circ\else\textdegree\fi{}), $\ensuremath{\beta}$-Th${\mathrm{Si}}_{2}$ (2.41\ifmmode^\circ\else\textdegree\fi{}), and ${\mathrm{W}}_{3}$${\mathrm{Si}}_{2}$ (2.84\ifmmode^\circ\else\textdegree\fi{}). These compounds include the first superconducting germanides, ${\mathrm{V}}_{3}$Ge and ${\mathrm{Mo}}_{3}$Ge, which, together with ${\mathrm{V}}_{3}$Si and ${\mathrm{Mo}}_{3}$Si, crystallize in the cubic $\ensuremath{\beta}$-tungsten structure. The transition temperature of ${\mathrm{V}}_{3}$Si is apparently the highest known for any binary superconducting compound.