The Isotope Effect in Superconductivity. I. Mercury

The critical magnetic fields of various isotopic mixtures of mercury have been measured as a function of temperature. The critical magnetic field at any temperature is found to decrease with increasing average mass, and the critical temperature also decreases with increasing mass. The relationship M^1{2}T₂=const, connecting the critical temperature T₂ and the average mass number M, is established. Conclusions are drawn concerning the specific heats of the normal and superconducting states of the isotopes.