Influence of Pr-doping on magnetic phase transition and magnetocaloric effect of La0.7-xPrxBa0.3MnO3 manganite

We have investigated the effect of the isovalent substitutions of the larger La3+ by the smaller Pr3+ in polycrystalline La0.7-xPrxBa0.3MnO3 (x = 0, 0.1 and 0.2) on ferromagnetic (FM) phase transition and magnetocaloric properties. Using Banerjee's criterion plots, it was found that the phase transition for all samples is of second-order. The magnetic transition temperature is tuned to room temperature by the substitution of Pr in La0.7Ba0.3MnO3, but the maximum magnetic entropy change remains nearly constant about 4 J/kg K. According to magnetocaloric investigations, x = 0.2 sample has a quite high relative cooling power with 371.45 J/kg for Delta H = 5 T, which makes it an interesting cooling material. A local exponent n(T-C, H) was calculated to determine the field dependence of the experimental -Delta S-M. Recently, a master curve behavior for the magnetic entropy change is also followed by these specimens. (C) 2014 Elsevier B.V. All rights reserved.