SPECIFIC-HEAT OF FERROMAGNETIC COMPOUNDS RNI

The specific heats of the ferromagnetic compounds ErNi, GdNi, and HoNi were measured by means of the adiabatic method in the temperature range 2.2-100 K. The specific heats for these samples showed anomalies corresponding to the magnetic orders. For the result of ErNi above Tc we could analyze by Cv=γT+αT3. The electronic specific heat coefficient γ and the Debye temperature θD were estimated to be 90 mJ/mol K2 and 130 K, respectively. The magnetic entropy was discussed on the basis of the energy-level splitting due to the crystalline field.