Structural study of the Ba6-x-yLa8+2/3x+yTii8-y Aly O54 solid-solution

The study of the Ba/La order in the Ba6-x-yLa8+2/3x+y Ti^.y Aly O54 solid-solution was performed by X-ray diffraction on single-crystals. The crystal structure of these phases belongs to the tetragonal tungsten bronze type, build on the basis of (3x3) TiO6 octahedron more than (2X2) (space group Pnma, a»22.4A, b»7.7 A, c»12.2 A). The substitution of titanium by aluminum within the Ba6-x La8+2/3x Ti18 O54 solid-solution concerns preferentially the two crystallographic sites Ti(1) and Ti(3) of the structural model.