Pyroelectric properties of valine doped TGS single crystals

Abstract

TGS was grown by a slow cooling technique adding several kinds of dopants (10 and 20 mole% alanine, 10% alanine + LiVO₃, 10% and 20% valine) to an aqueous solution. The temperature dependent pyroelectric coefficient, p and the spontaneous polarization, P_s, of doped-TGS crystals were measured to study the transition temperature, P_max and room temperature pyroelectric coefficient depending on the dopants and to calculate the figure of merit, (p/K), (K is a dielectric constant). Furthermore, several pieces were selected to investigate the positional inhomogeneities of the same sample. Moderate figure of merit (p/K) was obtained in valine doped TGS because of low temperature dielectric relaxation around −10°C, although valine doped TGS has a three times higher pyroelectric coefficient (p = 1.671μC/cm²K) at transition temperature (T_c) than that of alanine doped TGS.