Study of the Magnetocaloric Effect and Critical Behavior in Double Perovskite Manganese Oxides Pr_1.5A_0.5Mn₂O₆ (A = Mg, Ba)

In this study, polycrystalline samples of Pr₂Mn₂O₆ (parent phase) and Pr_1.5A_0.5Mn₂O₆ (A = Mg, Ba) were prepared using the high-temperature solid-phase reaction method. The effects of Mg and Ba doping on magnetocaloric properties and critical behavior of the parent phase were systematically investigated. Under a magnetic field of 7 T, the relative cooling power (RCP) values of Pr₂Mn₂O₆, Pr_1.5Mg_0.5Mn₂O₆, and Pr_1.5Ba_0.5Mn₂O₆ were approximately 483.46 J·kg⁻¹, 428.22 J·kg⁻¹, and 479.88 J·kg⁻¹, respectively. The critical behavior analysis revealed that the parent phase showed short-range exchange interactions, while Pr_1.5A_0.5Mn₂O₆ (A = Mg, Ba) exhibited long-range exchange interactions. The temperature dependence of the order parameter n was studied under different magnetic fields, confirming the phase transition types and validating the accuracy of the critical exponents obtained. The research findings suggest that both the parent phase and Ba-doped ceramics at the A-site hold promise as magnetic refrigeration materials.