THE RESEARCH OF BISMUTH ORTHOGERMANATE IMPEDANCE BY EQUIVALENT CIRCUITS METHOD

Using a computer approximation of impedance hodographs within the method of equivalent circuits it was found that the impedance spectrum of Bi4Ge3O12 single crystals at temperatures above 600 K contains three semicircles. It corresponds to Voigt circuit from three RC parallel circuits. It is suggested that high-frequency process of charge transport is caused by the hole conduction through volume of the crystal sample and mid-frequency process is connected with the migration of the space charge which appears near contacts due to the depletion of the majority carriers as a result of the recombination.