Photoferroelectric effects in BaTiO3 crystals

Abstract Intrinsic photo-induced changes in the hysteresis response in BaTiO3 single crystals have been observed by the application of ultra-violet (UV) light in combination with an applied bias. This UV/bias treatment suppresses the amount of switchable polarization by over 90%. The photoferroelectric effects observed are reproducible, reversible, and stable. Electron paramagnetic resonance measurements were also made to characterize the charge trapping associated with these hysteresis effects. The EPR results suggest that isolated Fe impurity sites are charge trapping centers in these crystals, and follow trends similar to those measured electrically. These results also re-enforce the idea that charge trapping centers can lock certain domain configurations.