SOME DIELECTRIC AND PHOTOREFRACTIVE PROPERTIES OF BI-BATIO3 AND BI,K-BATIO3 CRYSTALS

We report experimental results on the dielectric properties of Bi-dope d BaTiO3 and Bi, K double doped BaTiO3 crystals. The Curie temperature T-C of these crystals is about 1 to 2 degrees C lower than that of un doped BaTiO3 crystal, when the Bi doping concentration is less than 35 0 ppm and the K doping concentration is less than 155 ppm, respectivel y. When the Bi and K doping concentrations are increased, the Curie te mperature T-C and the dielectric constants both increase. The SPPC (se lf-pumped phase conjugation) reflectivity of Bi:BaTiO3 remains nearly the same as that of undoped BaTiO3, when the Bi doping concentration i s less than 123 ppm. However, the reflectivity of Bi,K:BaTiO3 decrease s because of the higher conductivity of these crystals.