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

Abstract We have investigated the effect of the isovalent substitutions of the larger La 3+ by the smaller Pr 3+ in polycrystalline La 0.7− x Pr x Ba 0.3 MnO 3 ( 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 La 0.7 Ba 0.3 MnO 3 , 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 Δ 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 −Δ S M . Recently, a master curve behavior for the magnetic entropy change is also followed by these specimens.