J. Phys. Colloques 33 (1972) C2-206-C2-208
X-RAY TOPOGRAPHIC STUDY OF DOMAIN WALL MOVEMENT IN T. G. S.A. IZRAEL, J. F. PETROFF and A. AUTHIER
Laboratoire de Minéralogie Cristallographie, associé au C. N. R. S. Université Paris VI, 9, quai St-Bernard, Paris V
During the X-Ray study of domains in ferroelectric T. G. S., we noticed random fluctuations of the X-Ray intensity diffracted by the sample. These fluctuations are shown to be related with domain boundaries oscillations due to a thermal gradient between the faces and the core of the sample, as the external temperature of the sample fluctuates. The understanding of this effect led us to attribute a special specific heat to the domain boundaries. The specific heat of a multidomain sample is therefore bigger than that of a monodomain sample. The increase of the number of domains and therefore of the walls in the vicinity of the Curie point allows us to give, with a semi-quantitative agreement, an interpretation for the difference between the specific heat increase observed experimentally (Taraskin  and Strukov ) and the increase predicted by the thermodynamical theory.