J. Phys. IV France 126 (2005) 27-30
DOI: 10.1051/jp4:2005126006

Piezoelectric properties at high temperature in -quartz materials

O. Cambon¹, J. Haines¹, G. Fraysse¹, D.A. Keen² and M.G. Tucker<sup>3

1</sup>  Université Montpellier II, Laboratoire de Physicochimie de la Matière Condensée, UMR CNRS 5617, Place E. Bataillon, 34095 Montpellier Cedex 05, France
²  Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK and ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK
³  Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK

Abstract
The performances of resonators made of -quartz and GaPO₄ are compared based on piezoelectric measurements up to 850°C. Up to now, no explanation was available for the observed decrease in piezoelectric performances well below the phase transition temperature in these materials. Total neutron scattering measurements were used to determine the instantaneous structural disorder as a function of temperature. The losses of piezoelectric properties measured above 700C for GaPO₄ can thus be correlated to an important degree of structural disorder, which is evaluated by various angular distributions. The distribution of the intertetrahedral O-O-O bridging angle values becomes very wide for this material between 700 and 800C. The relative movement of the tetrahedra can provide an explanation for the observed piezoelectric losses well before the phase transition.

© EDP Sciences 2005