TIME-DEPENDENCE OF FERROELECTRIC COERCIVE FIELD AFTER DOMAIN INVERSION FOR LITHIUM-TANTALATE CRYSTAL

We found the ferroelectric coercive field of LiTaO3, both in forward and reverse direction, vary with time after the domain is inverted. The coercive held drops when the domain is inverted, then gradually recovers. This phenomenon is light sensitive. The existence of a net time-varying internal electric field after domain inversion is hypothesized. The internal field is composed of the depolarization field, which is due to the spontaneous electric dipole moments, and an opposite direction time-varying space-charge field which is due to the redistribution of free-carriers transport under the influence of the depolarization field. Electro-optical effect caused by the internal electric field has been observed by means of an in situ optical monitoring technique for the domain inversion process. The in situ optical monitoring technique is based on using the LiTaO3 thin-plate crystal asa low finesse Fabry-Perot interferometer. (C) 1995 American Institute of Physics.