Synthesis of Perovskite Pr1.1MnO3.15 and Phase Evolution and Magnetic Properties

Abstract

Pr1.1MnO3.15 precursor was synthesized by solid-state reaction at low temperatures using Pr(NO3)3⋅6H2O, MnSO4⋅H2O, and Na2C2O4 as raw materials. Pr1.1MnO3.15 was obtained by calcining a precursor, 1.1/2Pr2(C2O4)3–MnC2O4⋅5.3H2O, over 1,000 ∘C in air. The precursor and its calcined products were characterized by thermogravimetry and differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometer. A high-crystallized Pr1.1MnO3.15 with an orthorhombic structure was obtained when the precursor was calcined over 1,000 ∘C in air for 2 h. Magnetic characterization indicated that orthorhombic Pr1.1MnO3.15 behaved with weak magnetic properties. The thermal transformation of the precursor from ambient temperature to 1,050 ∘C in air presented four steps: the dehydration of 5.3 crystal waters; the reaction of MnC2O4 with 0.75O2 into 1/2Mn2O3 and the two CO2 molecules; the reaction of 1.1/2Pr2(C2O4)3 with 0.825O2 into 1.1/2Pr2O2CO3 and of 2.75CO2 molecules; and the reaction of 1.1/2Pr2O2CO3 with 1/2Mn2O3 into Pr1.1MnO3.15 and 0.55CO2