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Structural phase transition in lanthanum gallate as studied by Raman and X‐ray diffraction measurements
Author(s) -
Dhak P.,
Pramanik P.,
Bhattacharya S.,
Roy Anushree,
Achary S. N.,
Tyagi A. K.
Publication year - 2011
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201046463
Subject(s) - orthorhombic crystal system , crystallography , lanthanum , diffraction , gallate , raman spectroscopy , x ray crystallography , phase transition , octahedron , materials science , phase (matter) , chemistry , condensed matter physics , crystal structure , physics , optics , inorganic chemistry , nuclear chemistry , organic chemistry
Lanthanum gallate (LaGaO 3 ) 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 GaO 6 octahedra, in both orthorhombic and rhombohedral phase.