Synthesis and electrical properties of Ln<inf>2</inf>(V<inf> 4 3</inf>W<inf> 2 3</inf>)O<inf>7</inf> pyrochlores

Mixed oxides of the type Ln2(V3+ 4 3W6+ 2 3)O7, Ln=GdLu, Y have been synthesized in vacuum via solid state reactions of the constituent oxides at 1150-1300°C. The compounds, which crystallize in cubic pyrochlore structure (a ∼ 10.2 A ̊), have been characterized by X-ray, density and wet chemical analysis. Electrical resistivity and Seebeck coefficient measurements show the phases to be p-type extrinsic semiconductors with low energies of activation possibly exhibiting hopping-type behavior. © 1979.