Superconductivity at High Pressure in the A15 Compounds

The superconducting transition temperature for a number of A15 compounds has been determined as a function of hydrostatic pressure up to 25 kbar. The observed pressure dependences are compared with the predictions of a number of correlations between T-c and volume derived from zero-pressure data. The limitations of the theoretical models used to calculate T-c for the transition metals and their alloys when applied to a description of the pressure dependence are discussed.