NEW OXYGEN-DEFICIENT PEROVSKITE RELATED PHASES [BA2INA11-XCUXO5-DELTA]

Solid solutions of the type Ba2InAl1-xCuxO5-delta (0.25 less-than-or-equal-to x less-than-or-equal-to 1) have been synthesized by high temperature solid state reactions of the constituent oxides. They crystallize in a tetragonal cell with space group P4/mmm, Z = 1. (a = 4.2197(7), c = 7.9254(18)angstrom for the x = 0.5 composition). Powder x-ray Rietveld analysis using a double perovskite related structure led to satisfactory refinement of the model for the x = 0.5 sample, Ba2InAl0.5Cu0.5O4.75. The structure consists of alternate slabs of BaInO3 and Ba(Cu/Al)O1.75 along the c-axis. Magnetic susceptibility measurements give an effective moment of approximately 0.5 BM from the Curie-weiss region.