Structural phase transition in lanthanum gallate as studied by Raman and X‐ray diffraction measurements

Abstract

AbstractLanthanum gallate (LaGaO3) is known to undergo orthorhombic to rhombohedral first order phase transition at 150 °C. In this article we have shown that by introducing 2% La deficiency in the system, coexistence of above two phases can be obtained at lower temperature and a complete phase transition occurs at 200 °C. The evolution of structural parameters of the system with temperature is reported from X‐ray diffraction measurements and Rietveld analysis of the diffraction patterns. The change in local octahedral distortion due to 2% La deficiency is revealed through the shift in the phonon modes of GaO6 octahedra, in both orthorhombic and rhombohedral phase.