Effect of Sm substitution on magnetic and magnetocaloric properties of La0.7-xSmxBa0.3MnO3 (0 ≤ x ≤ 0.2) compounds

In the present paper we have studied the effect of Sm doping on the magnetic and magnetocaloric properties of La0.7-xSmxBa0.3MnO3 (0 ≤ x ≤ 0.2) compounds. These sample have been synthesized by conventional solid state reaction method. The analysis of synthesized samples by X-ray diffraction showed that the formation of single phase compositions and doping of La3+ by Sm3+ ion converted the chemical structure form rhombohedral (R-3C) to orthorhombic (Imma). The magnetic study measurement specified that the ferromagnetic double exchange interaction is weakened with increasing Sm content as a consequence of the curie temperature (Tc) shift in lower temperature from 340 K for x = 0, 290 K for x = 0.1 and 225 K for x = 0.2 compounds. Using the Banerjee's criterion plots, it is found that the phase transition for all samples in the second-order. All reported compounds exhibit a maximum and large magneto-caloric effect near the Curie temperature (Tc). The magnitude of the maximum magnetic entropy change is found to be decrease with increasing of Sm doping content i.e. 4.39 J/kg K for x = 0, 4.22 J/kg K for x = 0.1 and 2.48 J/kg K for x = 0.2 in applied field change of 5T. The trend of large entropy change and the convenient adjustment of the Curie temperature make these oxides useful for magnetic refrigeration in an extended high and low temperature even at near room temperature.