CHARACTERIZATION OF TIO2-BASED SENSOR MATERIALS USING IMMITTANCE SPECTROSCOPY

The ac electrical data, monitored in the frequency range 5 Hz equal to or less than f equal to or less than 13 MHz, are used to establish th e microstructure-property response of titania-based composite polycrys talline sensor materials. These electrical data, when analyzed utilizi ng the lumped parameter/complex plane analysis, reveal several contrib utions from simultaneously operating mechanisms to the terminal admitt ance of the grain boundary. The nature of the electrically conducting paths, consisting of the lumped series-parallel network in the microst ructure, is suggested via an equivalent circuit representation incorpo rating the underlying mechanisms in a systematic manner.