Domain reversal in stoichiometric LiTaO_(3) prepared by vapor transport equilibration

摘要

Domain reversal in stoichiometric lithium tantalate (LiTaO_(3)) single crystals prepared by vapor transport equilibrium (VTE) method was studied. Starting from a virgin VTE crystal and using water electrodes, the coercive fields were found to be 1.39±0.01 kV/cm and 1.23±0.01 kV/cm for the first poling and the second poling, respectively, indicating a built-in internal field of 0.08 kV/cm. The spontaneous polarization, P_(s) was 55.2±0.5 μC/cm~(2) and the Curie temperature was T_(c)=701±2.5?. The switching time, t_(s), exhibits an exponential dependence on the external field, E with activation energy of 10.84±0.22 kV/cm. No domain backswitching was observed. These properties are dramatically different from those of congruent and even near-stoichiometric compositions of lithium tantalate grown by Czhochralski method.