Short-range-long-range order transformation in the Bi4V2-xFexO11-y series

In the present work, we have studied the Bi4V2-xFexO11-y series in the full range of composition. The microstructural characterization performed by me ans of X-ray powder diffraction, electron diffraction, and high-resolution electron microscopy reveals the crystals as formed by two kind of domains, structurally related, which differ in the V(Fe)-O layers. Both types of dom ains intergrow in variable ratio as a function of the iron content, but the y appear to contain vanadium and iron in a random distribution. The doping process is not a simple substitution process, and microstructure in both ar eas together with chemical composition is interpreted in terms of short-ran ge-long-range ordering of the V-O and Fe-O polyhedra in the perovskite laye rs of the basic structure.