Influence of thermal treatment in oxidizing and reducing atmospheres on the composition and properties of solid solutions based on bismuth vanadate: (Bi,La)4(V,Me)2O11-y (Me = Ga, Zr, Cu)

Ceramic solid solutions (Bi1 - y La y ) 4(V1 - x Me x )2O11 - z (x, y < 0.2: Me = Zr, Ga, Fe, Cu) were prepared by solid-state reaction. It was shown that the annealing (973 K, reducing atmosphere H2/Ar (20/80)) of the samples whose compositions belong to the stability domains of α, β, and γ′ polymorphs increases their electronic conductivity by six orders of magnitude. The samples with low concentrations of dopant cations exhibited good compositional stability and a reversible change in their structure parameters. At the same time, the solid solutions with a high concentration of lanthanum cations and/or copper cations (y, x - 0.1) underwent partial decomposition. © 2010 Allerton Press, Inc.