Low Frequency Dielectric Dispersion in Ferroelectric Pb₅Ge₃O₁₁ Single Crystal

Abstract

The complex dielectric constant of single crystal of ferroelectric Pb 5 Ge 3 O 11 has been measured in a frequency range below kHz order as a function of temrerature. The dielectric dispersion observed around and above the Curie temperature T c is very much dependent on the sample thickness; the conventional Cole-Cole plot does not form a circular arc. In addition, an anomalous dip of the real part of the complex dielectric constant has been frequently observed at T c in a frequency range of kHz order; such a dip can be observed only in the specimen thiner than 1 mm. The observed dielectric dispersion is discussed.