SYSTEMATIC X-RAY-DIFFRACTION STUDY OF BA1-XKXBIO3 SINGLE-CRYSTALS

Crystal structures of ten Ba1-xKxBiO3 single crystals (BKBO), grown by the anodic electrocrystallization process, were analysed to compare w ith previous studies on sintered powder samples. Results show that BKB O prepared in this way exhibit the same crystal symmetry of space grou p Pm3m for a wide range of x-values (0.39 to 0.66) and also indicates that there are solubility distrbutions both for potassium and oxygen. Oxygen deficiency lowers the superconducting transition temperature T- c. Electron density maps, calculated from room temperature X-ray diffr action data, do not show conspicuous difference between superconductin g and nonsuperconducting samples.