Europhys. Lett., 51 (3), p. 268 (2000)

New phase boundary and high-pressure
thermoelasticity of ZnO

F. Decremps ¹ - J. Zhang ¹ - R. C. Liebermann ²

 ¹ Mineral Physics Institute, SUNY at Stony Brook - Stony Brook, NY 11794, USA
 ² Department of Geosciences, SUNY at Stony Brook - Stony Brook, NY 11794, USA

PACS :
07.35.+k - High-pressure apparatus and techniques; shock tubes; diamond anvil cells
64.70.Kb - Solid-solid transitions
81.30.Dz - Phase diagrams of other materials

fad@pmc.jussieu.fr

Abstract:

The phase transition of zinc oxide from B4 (hexagonal wurtzite structure) to B1 (cubic rocksalt structure) has been studied by energy-dispersive powder diffraction technique up to 11 GPa and 1273 K. Analysis of equation-of-state (PVT) data for the rocksalt phase yields precise values of the bulk modulus and its temperature derivative. The previously accepted P-T phase diagram is shown to be incorrect. It is established that the B1 phase is not recoverable. The equilibrium transition pressure of the B4-to-B1 transformation is near 6 GPa (at ambient temperature) and the dP/dT slope close to zero. These new results are confirmed by using simultaneously three other different types of experiment (imaging, ultrasonic and X-ray diffraction studies on single-crystal specimens).

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