Superconductivity of thorium hydrides and thorium deuterides

Motivated by the possibility that a metallic hydride with a high hydrogen to metal atom ratio would be superconducting» we have tested the superconductivity of thorium hydrides and found that Th4 H15 is a superconductor with a transition temperature near 8K, Measurements of the diamagnetic susceptibility of 24 thorium hydride and thorium deuteride samples of various compositions have been made to determine the effect of composition and of hydrogen isotope on the superconducting transition temperature, The transition temperatures ranged from 6,8 to 8,4K for samples with hydrogen compositions greater than the dihydrides~ while the transition temperatures are less than l,lK for the dihydtide and dideuteride samples, No hydrogen isotope effect was found outside the 5% uncertainty in transition temperature, The specific heat of Th4 H15 has been measured in order to determine a jump in the heat capacity that is characteristic of bulk superconductivity, No discontinuous change in the specific heat was found indicating that the transition temperature was smeared out or that the superconductivity is not characteristic of the bulk material, The effect of heat treatment was also studied,U of I OnlyThesi