PHOTOINDUCED HYSTERESIS CHANGES AND CHARGE TRAPPING IN BATIO3 DIELECTRICS

We have been able to observe intrinsic photoinduced changes in the hysteresis response of BaTiO3 single crystals by the application of ultraviolet (UV) light in combination with an applied bias. The amount of switchable polarization can be suppressed by over 90% by this UV/bias treatment. The photoferroelectric effects are reproducible, reversible, and stable. Electron paramagnetic resonance measurements were also made to characterize the charge trapping associated with these electrical effects. We find that isolated Fe sites are trap centers in these ceramics and it appears that the Fe3+ density can be correlated to the amount of switchable polarization. These results also suggest that BaTiO3 ceramics can be used as a medium to store optical images.