PYROELECTRIC PROPERTIES OF VALINE DOPED TGS SINGLE-CRYSTALS

TGS was grown by a slow cooling technique adding several kinds of dopa nts (10 and 20 mole% alanine, 10% alanine + LiVO3, 10% and 20% valine) to an aqueous solution. The temperature dependent pyroelectric coeffi cient, p, and the spontaneous polarization, P-s, of doped-TGS crystals were measured to study the transition temperature, P-max and room tem perature pyroelectric coefficient depending on the dopants and to calc ulate the figure of merit, (p/K), (K is a dielectric constant). Furthe rmore, several pieces were selected to investigate the positional inho mogeneities of the same sample. Moderate figure of merit (p/K) was obt ained in valine doped TGS because of low temperature dielectric relaxa tion around -10 degrees C, although valine doped TGS has a three times higher pyroelectric coefficient (p = 1.671 mu C/cm(2)K) at transition temperature (T-c) than that of alanine doped TGS.