Synthesis and electrical properties of perovskite oxides, LnB<inf>0.75</inf>B′<inf>0.25</inf>O<inf>3</inf>

A series of ordered perovskite oxides of the type Ln2+0.75B′6+0.25O3 (Ln = rate earth or Y; B = Mn, Fe, Co, Ni; B′ = Mo, W, Re) has been synthesized and characterized by X-ray analysis and density measurements. Compounds with Ln = La are easily formed in all cases as single-phase materials and have either cubic or orthorhombic symmetry. When Ln = rare earth or Y, single-phase materials are formed only in the case of LnFe0.75Mo0.25O3 and these possess an orthorhombic structure. All the phases tested are extrinsic semiconductors in the range of 25-350°C, with Ea ranging from 0.1 to 0.4 eV. Resistivity of the Ln(Fe, Mo)O3 series of oxides increases from Ln = La to Ln = Lu. Ni-containing compounds are p type, while those containing Fe or Co in the B sites are n type. © 1980.