Superconductivity in germanium clathrateBa8Ga16Ge30

Abstract

We report type-II superconductivity in the germanium clathrate compound, ${\mathrm{Ba}}_8{\mathrm{Ga}}_{16}{\mathrm{Ge}}_{30}$ with critical temperature, $T_c=7.5\mathrm{}\pm 0.2\mathrm{K}$ as determined by magnetic susceptibility measurements. Barium atoms occupy cage voids provided by a covalent ${\mathrm{sp}}^3$ hybridized network of gallium and germanium. Magnetic susceptibility and transport measurements were used to characterize the transition.