Some semiconducting properties of Barium Titanate

Abstract

A number of single crystals of barium titanate have been grown by the flux melt process. These have been rendered semiconducting by reduction in hydrogen at 800 C for times up to 15 min. The resistivity, Seebeck coefficient and optical absorption coefficient have been measured in these crystals to obtain information about the conduction processes. The temperature of the tetragonal to cubic transition in the reduced crystals has been measured and is shown to be consistent with the results of the resistivity and Seebeck data. The results obtained are consistent with the theory that electrical conduction in these crystals is in the small polaron hopping mode with a drift mobility at room temperature of about 4 X 10(^-4)cm(^2)/V.s. with polaron concentrations reaching a peak of 4.18 X 10(^20)cm(^-3).The variation of polaron concentration with reduction time is similar to that obtained by Arend et al. by chemical analyses.