Magnetocaloric Effect and Critical Behavior Investigations in La_0.45Pr_0.2Sr_0.35MnO₃ Manganite Oxide

Structural, magnetic, and magnetocaloric effect (MCE) properties and the critical behavior of the La_0.45Pr_0.2Sr_0.35MnO₃ sample prepared by the sol–gel method have been investigated. The X-ray diffraction characterization reveals that our sample crystallizes in the orthorhombic structure with Pnma space group. Magnetization versus temperature measurement shows that our compound exhibits a ferromagnetic–paramagnetic transition. The Curie temperature is found to be 348 K. Close to this temperature, the maximum values of the magnetic entropy change (ΔS_M) and the relative cooling power (RCP) are found to be 2.84 J/kg/K and 230 J/K under µ₀H = 5 T, respectively. The Arrott plots revealed that this compound exhibits a second-order magnetic phase transition at T_C. The critical behavior has been investigated by several techniques which are the modified Arrott plot method, the Kouvel–Fisher method, and the critical isotherm analysis. The obtained critical exponents β, γ, and δ are consistent with those predictions of the mean-field model. Their reliability was confirmed by Widom's scaling relation, as well as the universal scaling hypothesis.