Effect of niobium substitution in stoichiometric lithium tantalate (SLT) single crystals

Optical-quality near-stoichiometric lithium tantalate (SLT) crystals doped with Nb were grown by top seeded solution growth technique using induction-heating system. The crystalline wafers were subjected to optical transmittance studies and coercive field measurements. The optical transmittance spectra of doped crystals show a shift in the absorption edge towards longer wavelength side. A change in Curie temperatures with respect to doping concentrations of Nb has been observed. Hysteresis measurements reveal that the coercive field value increases for increasing niobium concentration. It has also been observed that there is a significant increase in the internal field value for Nb-doped SLT crystals.