STRUCTURE AND MAGNETIC PROPERTIES OF Pr0.7A0.3MnO3 (A = Ca, Sr, Ba) CERAMICS PREPARED BY COMBINATION OF REACTIVE MILLING AND HEAT TREATMENT METHODS

Abstract

Pr0.7A0.3MnO3 (with A = Ca, Sr, Ba) ceramics belonging to an orthorhombic structure were successfully prepared by a combination of the reactive milling and the heat treatment methods. Based on experimental data of X-ray diffraction and M (H,T), the effect of cation replacement at Pr/A-site on the structure and the magnetic properties of the Pr0.7A0.3MnO3 (A = Ca, Sr, Ba) system has been carefully investigated. The results show a change in the lattice parameters and a significant shift in the ferromagnetic-paramagnetic phase transition temperature (TC) when a part of the Pr³⁺ ion was replaced by a larger ion (Ca²⁺ , Sr ²⁺ , and Ba²⁺). Under an applied magnetic field change of 10 kOe, Pr0.7Sr0.3MnO3 sample stands out clearly in a large magnetocaloric effect near room temperature with the characteristic values such as |Smax| and Cpmax about 3.06 and 95.82 J/kgK, respectively.