Effect of Monovalent Cation Doping on Structural,Magnetic, and Magnetocaloric Properties of Pr0.85A0.15MnO3 (A = Ag and K) Manganites

A systematic study on the effect of monovalent cation doping on structural, magnetic, and magnetocaloric properties of Pr_0.85 A _0.15MnO₃ (A = Ag and K) samples synthesized by a sol-gel method has been carried out. The crystal structure and morphology have been worked by X-ray diffraction (XRD) and scanning electron microscopy (SEM) imaging measurements. The XRD results indicate that both samples have orthorhombic structure. Magnetization versus temperature measurements show that our samples display a ferromagnetic-to-paramagnetic phase transition with increasing temperature. The ferromagnetic-to-paramagnetic phase transition temperature (T _C) values were found as 74 and 116 K for Pr_0.85Ag_0.15MnO₃ and Pr_0.85 K _0.15MnO₃, respectively. The magnetic entropy changes were evaluated from isothermal magnetization curves measured at various temperatures near T _C by steps of 4 K. The values of the magnetic entropy change were determined as 0.99 and 1.39 J kg ^?1 K ^?1 for Pr_0.85Ag_0.15MnO₃ and Pr_0.85 K _0.15MnO₃ under external field changes of 10 kOe, respectively.