Superconductivity of Hydrides and Deuterides of Thorium

Superconductivity has been observed in the hydrides and deuterides of thorium with H-or D-to-metal atom ratios of 3.6 to 3.65. Transition temperatures fall in the range from 8.05 to 8.35 K. These materials are apparently type-II superconductors with $H_{c2\mathrm{}}$ of the order of 25-30 kG at 1.1 K. There is no evidence for an isotope effect within the limits of experimental uncertainty.