Electronic conductivity and oxygen permeation properties of analogous compounds of SrO(SrTiO3)n (n = 1, 2) and SrTiO3 were investigated. Electronic conductivity and oxide ion conductivity decrease with increasing n, and SrTiO3 showed much higher conductivity. The effects of Co doping on oxide ion conductivity and electronic conductivity were also examined and it was observed that it was effective for increasing electrical conductivity and the oxygen permeation rate. Hall effect measurements suggested that the low electron-hole conductivity in Co-doped SrO(SrTiO3)n (n = 1, 2) could be assigned to a low mobility, which might result from the low electron and atomic density in the Sr–O rock-salt layer. Quantum mechanical calculations of the electron density also indicated low electron density in the rock-salt layer. This study revealed that the rock-salt layer consisting of Sr–O disturbs electron transfer in SrTiOX oxide and that the perovskite layer had much higher electronic and oxide ionic conductivity.

Effects of Rock-Salt Layer on Electronic and Oxide Ionic Mixed Conductivity in Strontium Titanate, SrO(SrTiO3)n (n = 1, 2, ∞). N.Sirikanda, H.Matsumoto, T.Ishihara: Solid State Ionics, 2010, 181[5-7], 315-21