The Ruddlesden–Popper ferrite Sr3Fe2O6+δ and its titania-doped derivatives Sr3Fe2-xTixO6+δ, where x ranged from 0 to 2, were characterized by X-ray powder diffraction and thermogravimetry. The changes in O content and crystal lattice parameters were consistent with Ti ions entering the solid solution in 4+ oxidation state with octahedral O

 coordination. Electronic conductivity measurements on polycrystalline Sr3Fe2O6+δ and Sr3Fe0.8Ti1.2O6+δ at 750 to 1000C and O partial pressures (pO2) varying from 10-20 to 0.5atm revealed that the predominant partial conductivity of electrons was proportional to pO2-1/4 in the low pO2 region, while the predominant partial contribution of holes to the conductivity was proportional to pO21/4 in the high pO2 range. The pressure-independent O ion conductivity was found to decrease with the increase in Ti content. A possible pathway for O ion migration was proposed in relation to disorder in the O sub-lattice and Ti doping.

Order–Disorder Enhanced Oxygen Conductivity and Electron Transport in Ruddlesden–Popper Ferrite-Titanate Sr3Fe2-xTixO6+δ. Y.A.Shilova, M.V.Patrakeev, E.B.Mitberg, I.A.Leonidov, V.L.Kozhevnikov, K.R.Poeppelmeier: Journal of Solid State Chemistry, 2002, 168[1], 275-83