Investigation on the magnetocaloric effect in RNi2 (R: Dy, tb) melt-spun ribbon

Abstract We report a theoretical and experimental investigation on the magnetocaloric properties of the rare earth RNi 2 (R=Dy,Tb) in melt-spun ribbon and bulk form. The theoretical calculations were performed using a Hamiltonian model including the Zeeman-exchange interactions and the crystalline electrical field. Thus the magnetocaloric potential was calculated in the easy magnetic axes, in order an average over all of the possible directions. The isothermal entropy-change dependence on temperature calculated was compared with available experimental data for melt-spun ribbon and bulk material. We also investigated, theoretically and experimentally, the behavior of a DyNi 2 and TbNi 2 composite with optimized molar proportions and discussed this in the context of the optimum regeneration Ericsson cycle.