Electric-field-induced giant strain in Bi_0.5Na_0.5TiO₃-based single crystals: Influence of high-oxygen-pressure annealing

抄録

Influences of high-oxygen-pressure (350 MPa) annealing on the properties of leakage current, polarization, and strain were investigated for single crystals of (Bi_0.5Na_0.5)TiO₃-(Bi_0.5K_0.5)TiO₃-BaTiO₃ with P4mm tetragonal structure The oxygen annealing led to a marked increase in leakage current, showing that the oxidized crystals have a high concentration of electron hole (carrier) and a low concentration of oxygen vacancy compared with the crystals annealed in air. While the air-annealed crystals exhibited a giant strain up to 0.8% at an electric field of 40 kV/cm, the oxidized crystals showed a small strain less than 0.3%. The results can be explained by the interaction between ferroelectric domains and charged defects.