Phase relations, chemical diffusion and electrical conductivity in pure and doped Sr4Fe6O13 mixed conductor materials

Phase relations and transport properties of undoped and La and/or Ti-doped Sr4Fe6O13 have been studied. In the doped materials significant amounts of perovskite SrFeO3-delta were formed together with SrFe12O19. An intergrowth on nanoscale of SrFeO3-delta and Sr4Fe6O13 was observed in the TEM for the La-doped material. The content of La was higher in the SrFeO3-delta than i n the Sr4Fe6O13 phase. The electrical conductivity and chemical diffusion c oefficient of undoped and La/Ti-doped Sr4Fe6O13 have been measured and a de fect model for undoped Sr4Fe6O13 is presented. The transport properties of doped Sr4Fe6O13 reflect multiphase materials mainly dominated by the perovs kite phase. (C) 2000 Elsevier Science B.V. All rights reserved.