Electrical properties of the ferrite SrFeOy at high temperatures

The electrical properties of the strontium ferrite are reported within the temperature range 700 to 950 degreesC and the oxygen partial pressure range between 10(-18) and 0.3 atm, The observed pressure and temperature depende ncies of the conductivity in the brownmillerite form of the ferrite are rel ated to the transition of the electron conductivity from the intrinsic regi me, which is governed by the band gap of about 2 eV, to the extrinsic regim e, which is controlled by the extrastoichiometric oxygen in the brownmiller ite phase. The brownmillerite phase is shown to be a mixed conductor with t he oxygen conductivity rising to about 0.1 S/cm at 850-900 degreesC and p(O 2) > 10(-17) atm. The perovskite-like layers in the brownmillerite structur e provide a possible pathway for the ion migration, (C) 2001 Academic Press .