EFFECT OF OXYGEN-DEFICIENCY ON THE STRUCTURE AND CONDUCTION BEHAVIOR OF BAPB0.75BI0.25O3-DELTA

Oxygen-deficiency (delta) and its effect on the structure and electrical properties of BaPb0.75Bi0.25O3-delta were studied. Delta could be controlled from 0.00 to 0.15. It was observed that the crystal symmetry varied with increasing delta from orthorhombic (delta = 0.00 +/- 0.005) through tetragonal (delta = 0.09 +/- 0.005, 0.11 +/- 0.005) and to cubic (delta = 0.15 +/- 0.005). Electrical resistivity increased by increasing delta. The superconducting transition was observed at 13 K and 10 K in the specimens of delta = 0.00 +/- 0.005 and delta = 0.09 +/- 0.005, respectively. In the specimens of delta = 0.11 +/- 0.005 and 0.15 +/- 0.005, superconductivity was not observed.