The structural, magnetic and magnetocaloric properties of La0.67Ca0.33−xMgxMnO3 (x = 0, 0.02, 0.05, 0.1, 0.2, 0.33) compounds

In this study, the structural, magnetic and magnetocaloric properties of the polycrystalline La0.67Ca0.33−xMgxMnO3 (x = 0, 0.02, 0.05, 0.1, 0.2, 0.33) were systematically investigated. X-ray analyses indicated that the substitution of Ca by Mg produced no considerable structural change and only the diffraction peaks for orthorhombic symmetry were obtained for all samples. The Curie temperature was found to decrease with increasing Mg content from 267 K for x = 0 to 96 K for x = 0.33. The decrease in saturation magnetisation and Curie temperature were attributed to weakening of the ferromagnetism in Mg doped samples. The maximum value of the magnetic entropy change at 1 T decreased from 4.07 J/kg K for x = 0 to 0.41 J/kg K for x = 0.33. The decrease in magnetic entropy change was attributed to decrease in saturation magnetisation and nature of phase transition transformed from first-order to second order with increasing Mg content.