Structural Aspects and Ionic Conductivity in Perovskite-like Doped Niobates and Titanates

Aliovalent substitution in the cation sublattices of perovskite-like niobates of the type (Pb(1-x)La(2/3x-y)Li(3x))Nb(2)O(6) were studied. Their crystallographic peculiarities and electrophysical properties were investigated. It has been found that at x=1 lanthanum-lithium niobates with the structure of the defect La(2/3-y)Li(3y)Nb(2)O(3) perovskite are formed, which possess a high lithium-ion conductivity. The symmetry of the perovskite crystal lattice is shown to become higher and to change from rhombic to tetragonal and cubic with increasing lithium content. The La(2/3-x)LiTiO(3) compounds have a perovskite structure and a high lithium ion conductivity. The Lines model for superionic conductor gives a satisfactory fit to the frequency-temperature nature of the electrophysical properties.