INFLUENCE OF THE CRYSTALLINE ELECTRICAL-FIELD ON THE MAGNETOCALORIC EFFECT OF DYAL2, ERAL2, AND DYNI2

Calculations of the magnetic entropy change Delta S-mag and the magnet ocaloric effect (i.e., the adiabatic temperature change) Delta T-ad in DyAl2, ErAl2, and DyNi2 using a Hamiltonian that takes into account t he effects of crystalline electrical field and exchange interaction ha ve been carried out. Good agreement between the theory and the experim ent was obtained using the crystal-field parameters from inelastic neu tron scattering for DyAl2 and ErAl2. The crystal-field parameters for DyNi2, which were reported from magnetization measurements, did not gi ve good agreement between the theory and the experiment. Using the exp erimental Delta S-mag versus T, and C-mag versus T (where C-mag is the magnetic heat capacity) we made an estimate of the crystal-field para meters for DyNi2, which yield a satisfactory agreement between the the ory and the experiment with regard to Delta S-mag and Delta T-ad The a ppearance of a hump in the theoretical Delta S-mag(T) below the Curie temperature is discussed. [S0163-1829(98)05642-2].