Thermodynamic study and intrinsic type II superconductivity in the A-15 compound V₃Si

The specific heat of a single crystal of the A-15-type compound V₃Si in the normal, mixed, and superconducting states has been measured from 4 to 30 K in magnetic fields up to 50 kOe. The analysis has been performed in a self-consistent way based on the second-order phase transition from the normal to the superconducting state. The thermodynamic critical field and then various physical parameters characterizing the superconducting and normal states are almost consistently derived from the thermodynamics and the microscopic BCS-GLAG theory. It is confirmed that V₃Si is an intrinsic type II superconductor with a high intrinsic GL parameter κ₀.