Superconductivity of Uranium

Abstract

A ballistic mutual-inductance technique has been employed to investigate the magnetic susceptibility of two uranium samples down to a temperature of 0.1\ifmmode^\circ\else\textdegree\fi{}K. Both samples exhibited a superconducting transition in zero magnetic field at a temperature (${T}_{c}$) of 0.68\ifmmode\pm\else\textpm\fi{}0.02\ifmmode^\circ\else\textdegree\fi{}K. The transitions were not sharp, being spread over a temperature interval of 0.45\ifmmode^\circ\else\textdegree\fi{}K. The critical magnetic field of one of the samples was measured down to 0.37\ifmmode^\circ\else\textdegree\fi{}K and a value of 720 gauss/deg was obtained for ${(\frac{\mathrm{dH}}{\mathrm{dT}})}_{T={T}_{c}}$. Consideration is given to the values of the electronic specific heat coefficients derived from the critical magnetic field data for uranium and titanium.