Journal of the Physical Society of Japan · 1981 · 14 citations · 3 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsSolid State PhysicsSolid-state ChemistryCrystal ChemistryCrystallographyPhase DiagramsPhase EquilibriaPhase TransitionsSolid-state Phase TransitionsCrystallographic Phase TransitionsEntropy ChangePressure CoefficientsPressure-temperature Phase BehaviorPressure-temperature Phase DiagramsTemperature-pressure Phase EquilibriaThermal ExpansionThermal Expansion Of Crystals
The experimental results of dilatation and the temperature-pressure phase diagrams for Pb 3 (VO 4 ) 2 and Pb 3 (PO 4 ) 2 crystals are presented. The pressure coefficients of transition temperatures between the trigonal and the nonpolar monoclinic phases d T 1 /d p and between the nonpolar and polar monoclinic phases d T 2 /d p for Pb 3 (VO 4 ) 2 were -12.1 and 20.2 deg/kbar, respectively. The intermediate monoclinic phase II of Pb 3 (VO 4 ) 2 vanishes at a triple point of 3 kbar and 65°C. The d T 1 /d p for Pb 3 (PO 4 ) 2 was -9.8 deg/kbar, but no triple point was observed. The entropy change estimated for Pb 3 (VO 4 ) 2 on the basis of obtained data suggests that the transition mechanism in this crystal is likely to be of the order-disorder type.
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Calcium orthovanadate, Ca3(VO4)2-a new high-temperature ferroelectric
A. M. Glass, S. C. Abrahams, A. A. Ballman et al. · Ferroelectrics · 1977 · 87 citations