The magnetocaloric properties in the series $R{\mathrm{Ni}}_2$ $(R=\mathrm{Pr},$ Nd, Gd, Tb, Ho, Er) were fully investigated using a model Hamiltonian that includes the exchange magnetic interaction and the crystalline electrical-field anisotropy. All theoretical results was obtained using the proper model parameters found in the literature for the compounds belonging to this series. For ${\mathrm{ErNi}}_2$ we obtained a good agreement between theoretical and experimental data in the magnetocaloric potentials. An anomalous second peak was predicted to exist in the magnetocaloric curves for ${\mathrm{HoNi}}_2$ and it was ascribed to the high density of states at low temperature.

• Received 19 December 2000

DOI:https://doi.org/10.1103/PhysRevB.63.184406