Eur. Phys. J. B 30, 153-160 (2002)
https://doi.org/10.1140/epjb/e2002-00370-y

Factory-roof-shaped phase front at the paraelectric-ferroelectric transition in KD₂PO₄: an incoherent interface

Laboratoire de Spectrométrie Physique (Unité associée au CNRS 8) , Université Joseph Fourier, BP 87, 38402, Saint-Martin d'Hères, France

Corresponding author: ^a jean.bornarel@ujf-grenoble.fr

Received: 25 April 2002
Published online: 29 November 2002

Abstract

The phase front during the 218 K transition in KD₂PO₄ crystals under a thermal gradient perpendicular to the c ferroelectric axis is observed to have a factory-roof shape. This shape is studied versus the magnitude of G_e in samples cut with faces in (100), (010), (001) planes or in (0), (110), (001) ones. A geometric approach as well as the calculation of the elastic-strain energy caused by lattice misfits along the phase front demonstrate the incoherent interface nature of the phase front. Furthemore, the results and their interpretation allow to predict the sign of the lattice deformation .