Critical exponents for anisotropic thermal expansion at ferroelectric Curie temperatures: Evidence for defect mechanisms
Department of Physics, Cavendish Laboratory, Cambridge University - Cambridge CB3 0HE, UK
Received: 16 August 2013
Accepted: 7 November 2013
The defect dynamical model of Sigov and Levanyuk is used to analyze a heretofore unsolved problem in ferroelectricity: the temperature change of anisotropic thermal expansion along the polar axis. For brominated tris-sarcosine calcium chloride a new expansion exponent in reduced temperature is found, in agreement with the Sigov-Levanyuk theoretical value, under the assumption that the change in thermal diffusion is proportional to the change in thermal expansion near Tc.
PACS: 64.60.fd – General theory of critical region behavior / 77.80.B- – Phase transitions and Curie point / 77.84.Fa – KDP- and TGS-type crystals
© EPLA, 2013