FIXABLE COMPLEMENTARY GRATINGS IN PHOTOREFRACTIVE BATIO3

A complementary photorefractive grating was created and stored in BaTiO3. For a grating wave vector oriented along the crystal's c axis, the grating first appeared above 80-degrees-C and would remain indefinitely after the crystal was cooled to room temperature. If the grating wave vector was aligned perpendicular to the c axis, the complementary grating could be created at room temperature but would last only a few hours. We attribute the formation of the complementary grating to the movement of ions in the crystal.