Investigation of the magnetocaloric effect and critical behavior of the perovskite La0.65Ca0.35-xBaxMnO3 (x=0, 0.1, 0.2, 0.3)

Polycrystalline samples of La0.65Ca0.35-xBaxMnO3 (x = 0, 0.1, 0.2, 0.3) were prepared using a conventional solid-state reaction method. The prepared samples demonstrated good single-phase quality, characterized by a space group of Pbnm. There was a significant increase in the relative cooling power (at 5T), with values as follows: RCP(x=0)approximate to 243J.kg(-1), RCP(x=0.1)approximate to 267J.kg(-1), RCP(x=0.2)approximate to 273J.kg(-1), and RCP(x=0.3)approximate to 292J.kg(-1). It is noteworthy that the sample with a doping level of x = 0.2 underwent a transition from a first-order phase transition to a second-order phase transition. The critical behavior of the x = 0.2 and 0.3 samples was analyzed using modified Arrott plots and the Kouvel-Fisher method to determine critical exponents. The results obtained from both methods were in close agreement, indicating that the critical behavior of the x = 0.2 and 0.3 samples can be described by the mean field model.