Field dependence of magnetocaloric properties of 20% Cr-doped Pr0.7Ca0.3MnO3 perovskite

Abstract

In this study, we have investigated the effect of 20% Cr doping at the Mn site on the magnetic and magnetocaloric properties of Pr0.7Ca0.3MnO3 polycrystalline manganites elaborated using the solid-state reaction. The X-ray powder diffraction shows that compounds crystallize in the orthorhombic system with Pnma space group. The parent compound Pr0.7Ca0.3MnO3 is a well-known charge-ordered (CO) compound. The selective substitution of Cr for Mn in the pristine compound destroys the CO ordering observed in Pr0.7Ca0.3MnO3, and a paramagnetic to ferromagnetic transition takes place. The field dependence of the magnetic entropy change ∆S and of the relative cooling power RCP is reported. The \(\left| {\Delta S^{\hbox{max} } } \right|\) are found to be 0.8 and 2.87 J kg−1 K in a magnetic field change of 5 T for x = 0 and 0.2, respectively. The RCP is found to be 253.2 J kg−1 in the Pr0.7Ca0.3Mn0.8Cr0.2O3 at 5 T. With the scaling laws, the experimental ∆S and n collapse onto a universal curve for Pr0.7Ca0.3Mn0.8Cr0.2O3 sample, where an average curve is obtained for ∆S. With the phenomenological universal curve, the magnetic entropy change ∆S curves are well predicted for Cr-substituted sample. Additionally, Banerjee’s criteria, the universal behavior and Landau theory of phase transitions were also studied to assess magnetic ordering in the Pr0.7Ca0.3Mn0.8Cr0.2O3 material.