Dielectric spectroscopy investigation on polar phase transitions

By using frequency and time domain dielectric spectroscopy, the polar phase transitions of (Ba1-xSrx)TiO3 ceramics have been studied, Compared with th e phase transitions of a ferroelectric crystal, the motion of space charges in ceramic has been obtained as well as lattice softening, excitation of s creen charges and motion of ferroelectric domains. Slow effect, which is co ntributed by ferroelectric domains and space charges, can affect the accura te measurement by frequency domain method. In this paper we describe this i nfluence and explain some experimental results. The reciprocal of frequency domain dielectric constant has a linear softening in the transition of pri mary structure, but has a parabolic type softening in that of high structur e.