Experimental Study of the Magnetocaloric Effect in the Pseudo Binary Laves-Phase Compounds

Polycrystalline samples of DyCo2, HoCo2, ErCo2 and their solid solutions Dy1-xHoxCo2, Dy1-xErxCo2, Ho1-xErxCo2 have been studied using X-ray diffraction analysis, heat capacity and magnetic measurements. The Xray diffraction performed at room temperature allowed to reveal that all solid solutions solidify with the formation of the C15 cubic Laves-phase structure corresponding to the Fd3m space group. All binary compounds and their solid solutions are typical ferrimagnets and are magnetically ordered at temperature below 140 K. In all doped solid solutions an decrease of the magnetic ordering temperature is observed. At high temperatures, all samples are Curie-Weiss paramagnets. The magnetization behaviour and the magnetic transition are analyzed in terms of Landau theory. The magnetocaloric effect has been estimated using the heat capacity data. Comparison of the influence of doping effect in pseudo-binary compounds on their magnetic and magnetocaloric properties for all solid solutions is presented.