Thermodynamics of the UPt3 superconducting phase diagram

In this paper we present a thermodynamic analysis of the UPt3 superconducting phase diagram in the H-T plane. The analysis relates the specific-heat jumps to the slopes of the four phase-transition lines. The existing data are found to be in good mutual agreement, and consistent with the assumption that the inner phase-transition line at low field, Tc*, is second order for both H and H. For H, the inner phase-transition line at higher field, HFL, is first order albeit with a small latent heat. For H, it can be second order.