Melting Pressure and the Phase Diagram of Magnetically Ordered SolidHe3

Abstract
From high-resolution measurements of the melting pressure of solid He3 in applied fields, we determine the entropy and order of the magnetic phase transitions. We find the entropy discontinuity at the first-order antiferromagnetic transition to decrease as the field increases. No entropy discontinuity is seen at the paramagnetic to high-field transition, indicating that it is not first order.