来源：Science Direct
This study investigates how the substitution of rare-earth elements influences the structural, microstructural, magnetic, and magnetocaloric properties of double perovskites R2ZnMnO6 (R = Y, Er, and Pr). Polycrystalline samples were prepared using the classical solid-state technique. X-ray diffraction refinement confirmed a single-phase monoclinic P21/n structure with a high fitting efficiency (χ2 = 1.58–1.69). Increasing the ionic radius of the rare-earth elements results in larger lattice parameters and unit cell volumes. Scanning electron microscopy analysis revealed a dense and homogeneous microstructure with well-developed grains and strong intergranular connectivity. Magnetic measurements demonstrated a significant dependence of magnetic behavior on the type of rare-earth ion, underscoring the strong relationship between structural distortion and magnetic exchange interactions. The largest magnetic entropy changes at 5 T (50 kOe) for Y2ZnMnO6, Er2ZnMnO6, and Pr2ZnMnO6 were found to be 5, 12, and 6 J kg−1 K−1, respectively, with corresponding refrigerant capacities of 170, 250, and 350 J kg−1. These results establish a direct correlation between crystal structure, magnetic interactions, and magnetocaloric performance, offering new insights into how rare-earth substitution affects the multifunctional behavior of double-perovskite oxides.