Ferroelectrics · 1978 · 11 citations · 1 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsPhysical ChemistrySolid State PhysicsCrystal SymmetryCrystal SystemsCrystallographyPhase TransitionsRaman SpectroscopyX-ray CrystallographyCrystallographic Symmetry AnalysisMonoclinic SystemNeutron Scattering TheoryPhenomenological InterpretationPhenomenological ModelsSymmetry Breaking In CrystalsSymmetry-allowed Transitions
Abstract Recent Raman, x-ray and neutron scattering measurements have cast a doubt on the validity of the accepted symmetry change C2/c ← R3m at the 180°C transition of Pb3(PO4)2. We show that these results can be interpreted satisfactorily with help of the existing phenomenological theory, by assuming the occurrence of a new monoclinic phase involving an 8-fold unit cell expansion, between 180°C and 300°C. Dielectric measurements have been performed to explore the validity of this scheme.
1