0000000001019583
AUTHOR
A. Lahlafi
Algebraic value of the electrooptic coefficients and nature of charge carriers in batio3single crystals
Abstract Some monodomain pure and Fe doped barium titanate monocrystals are studied. The algebraic values of the electrooptic coefficients r 13 and r 33 are evaluated using an interferometric method. Then, from energy transfer results it is possible to conclude that majority carriers are positive charges in all the samples.
Theoretical study of Fe doping and oxidation–reduction influence on the photorefractive effect in BaTiO_3
We numerically solve charge-transport and Poisson equations for photorefractive BaTiO3 single crystals with a band model, using four impurity levels, Fe2+–Fe3+, Fe3+–Fe4+, VO••–VO•, and VO•-VOx. Densities and photoinduced spatial distributions of each population are computed as a function of annealing O partial pressure. Space-charge field and beam-coupling gain are also computed as a function of annealing O partial pressure, temperature, Fe concentration, grating wave vector, and light intensity. We discuss the intervening mechanism of impurity centers and the correlations between experimental conditions of crystal growth, oxidation–reduction treatments, and measurement parameters.