Investigation on the magnetocaloric effect in DyNi2, DyAl2 and Tb1-nGdnAl2 (n=0, 0.4, 0.6) compounds

The magnetocaloric effect (MCE) in the DyNi2, DyAl2 and Tb1-nGdnAl2 (n=0, 0.4, 0.6) was theoretically investigated in this work. The DyNi2 and DyAl2 compounds are described considering a model Hamiltonian which includes the crystalline electrical field anisotropy. The anisotropic MCE was calculated changing the magnetic field direction from <1 1 1> to <0 0 1> in DyNi2 and from <1 0 0> to <0 1 1> in DyAl2. The influence of the second- and first-order spin-reorientation phase transitions on the MCE that occurs in these systems is discussed. For the calculations of the MCE thermodynamic quantities in the Tb1-nGdnAl2 systems we take into account a two sites magnetic model, and good agreement with the available experimental data was obtained.