Abstract: The present invention concerns a high vacuum in-situ refining method for high-purity and superhigh-purity materials and the apparatus thereof, characterized in heating the upper part and lower part of crucible separately using double-heating-wires diffusion furnace under vacuum, thereby forming the temperature profile which is high at upper part and low at lower part of crucible, or in reverse during different stages; then heating the crucible in two steps to remove impurities with high saturation vapor pressure and low saturation vapor pressure respectively in efficiency; and obtaining high-purity materials eventually. The whole procedure is isolated from atmosphere, reducing contamination upon stuff remarkably. The present invention could provide products with high-quality and high production capacity, which are stable in performance, therefore is reliable and free from contamination.

Abstract: The present invention relates to a doped barium titanate single crystal containing barium titanate as substrate and 5-250 ppm Ce, the process therefor and photorefractive devices made from the cerium doped barium titanate single crystal.