Heat capacity as a probe of surface phase transitions in thin antiferromagnetic films

External magnetic fields can produce a phase transition from an antiferromagnetic state to a spin-flop state in antiferromagnets. In ultrathin antiferromagnets. the critical magnetic field is sensitive to whether the net number of magnetic layers is odd or even. Wt show that this transition will produce a distinct feature in the heat capacity as a function of applied magnetic field. The feature is an the order of 5-10% of the magnetic heat capacity and should be measurable.