Sintering Temperature Dependence of Structural and Morphological Properties of PrMnO3 perovskite manganite

Abstract

PrMnO₃ perovskite manganite ceramics were synthesised using the conventional solid-state reaction method and sintered at 1000 °C, 1050 °C and 1100 °C to investigate the influence of sintering temperature on their structural and morphological properties. X-ray diffraction analysis showed that the main diffraction peaks of all samples correspond to an orthorhombic perovskite-related PrMnO₃ structure with Pnma symmetry. Rietveld refinement confirmed the orthorhombic lattice and revealed slight variations in lattice parameters, unit-cell volume, Mn-O bond length and Mn-O-Mn bond angle with sintering temperature. The χ2 value decreased from 1.680 for the sample sintered at 1000 °C to 1.463 for the sample sintered at 1100 °C, while the profile residuals showed some variation among the samples. Weak secondary reflections were observed, but their contribution was reduced with increasing sintering temperature. SEM micrographs showed progressive densification, clearer grain boundaries and reduced intergranular porosity as the sintering temperature increased. EDX analysis confirmed the presence of Pr, Mn and O as the main constituent elements in all samples. Among the investigated temperatures, the sample sintered at 1100 °C showed the most favourable structural and morphological development, with improved phase formation, lower secondary-phase contribution and denser microstructure. These findings demonstrate the important role of sintering temperature in controlling the structural and morphological characteristics of undoped PrMnO₃ ceramics.