Structure and Electrical Properties of Oxygen-Deficient Strontium Copper Niobate

The transport properties of Sr(5.66)Cu(0.14)Nb(2.20)O(11.30) double perovskite, which enters the homogeneity region of (Sr(1-y)Cu(y))(6-2x)Nb(2+2x)O(11+3x) solid solution, are concerned. The total conductivity is differentiated into terms over wide ranges of temperatures and oxygen partial pressures p(O2) in dry and humid atmospheres. When p(O2) is low or high, a test sample has dominant electron transport of n- or p-type, respectively. In air (p(O2) = 0.21 atm), the p-type electron conductivity term increases with temperature elevation. In a humid atmosphere (p(H2O) = 0.02 atm), a sample is capable of a reversible incorporation of water occlusion from the gas phase; as a result, some proton conductivity term appears and ion transference numbers increase over a wide range of p(O2) values.