Structural changes of LaBa2Cu3−yFeyOx cuprates with 0.0 ≤ y ≤ 0.50

Ceramic samples of LaBa2Cu3-yFeyOx cuprates with y = 0.00-0.50 are synthesized. Microstructures of these iron doped samples are studied by X-ray diffraction. Rietveld refinements give the lattice and atomic parameters for each iron doped sample. There are orthorhombic-to-tetragonal and tetragonal-to-orthorhombic phase transitions due to iron doping. The iron preferentially occupies the Cu(1) site as y less than or equal to 0.15 and the Cu(2) site as y greater than or equal to 0.25. The preferential occupancy of iron induces the local structural change and the phase transition. (C) 1997 Elsevier Science B.V.