抄録
Solubility of Cu to BaPbO3 was investigated by firing mixtures of BaO2, PbO2 and CuO at 890°C for 42hours. BaPb1-xCuxO3 type solid solution seemed to be formed in a compositional range of x<0.5. Two types of crystal structure were found out for the composition of Ba2Pb CuO ?? . The phase 1 had a hexagonal lattice with a=6.085Å, c=15.02Å, and phase 2 had a tetragonal lattice with a=4.293Å, c=17.25Å. They can be related to the cubic lattice parameter a'of BaPbO3 in relations of a??21/2a', c??2×31/2a' in the former, and a??a', c??4a' in the latter. These superlattices are due to the layer-by-layer orderings of copper oxide and lead oxide layers. The phase 1 changed to the phase 2 by firing 890°C in air flow for 20 hours and also even by keeping in ambient atmosphere for 4 days. The phase 1 was a semiconductor down to 4.2K with an electrical resistivity of 4.9×10Ωcm at room temperature.
