Analysis of pyroelectric and dielectric measurements on boracites

Abstract

Abstract The measured temperature dependence of the dielectric constant and pyroelectric coefficient in FeI, CuC1 and MnI boracites are analyzed according to the thermodynamic model advanced by Dvorak and Petzelt and by Gufan and Sakhnenko for the ferroelectric cubic-orthorhombic phase transition. A simplified form of their thermodynamic potential yields acceptable fits to the data over a large temperature interval. The values of the parameters obtained from the fits, however, are not consistent with the usual systematic neglect of high-order terms in the potential.