Oxygen transport in epitaxial SrTiO3/SrTi1 − xFexO3 multilayer stacks

Other literature type English OPEN
Schulz, Michal ; Orland, Timna ; Mehlmann, Alexander ; Rothschild, Avner ; Fritze, Holger (2017)

Nano-ionic materials made of strontium titanate (SrTiO<sub>3</sub>, STO) and solid solutions of strontium ferrite in STO (SrTi<sub>1 − <i>x</i></sub>Fe<sub><i>x</i></sub>O<sub>3</sub>, STF) are grown on single crystalline STO substrates and characterized. Since STF exhibits an oxygen deficiency and, simultaneously, enables oxygen interstitial defects, a space charge area close to the STO | STF interface is present. Oxygen tracer diffusion experiments and impedance spectroscopy at temperatures from 500 to 700 °C and at oxygen partial pressure ranging from 10<sup>−3</sup> to 10<sup>−23</sup> bar confirm fast oxygen transport caused by enhanced ionic conductivity at the interface. There, an oxygen diffusion coefficient of 3. 4 × 10<sup>−10</sup> m<sup>2</sup> s<sup>−1</sup> at 600 °C and a <i>p</i> type conductivity of about 360 S m<sup>−1</sup> at 700 °C are calculated. Such structures open new options in design of nano-ionic materials for oxygen sensors and energy conversion at temperatures lower than those of conventional materials such as yttrium-doped zirconia.
  • References (27)
    27 references, page 1 of 3

    Badwal, S.: Zirconia-based solid electrolytes: microstructure, stability and ionic conductivity, Solid State Ionics, 52, 23-32, 1992.

    Balachandran, U. and Eror, N.: Electrical Conductivity in Strontium Titanate, J. Solid State Chem., 39, 351-359, 1981.

    Chan, N.-H., Sharma, R., and Smyth, D.: Nanostoichiometry in SrTiO3, J. Electrochem. Soc., 128, 1762-1768, 1981.

    Comsol: COMSOL Multiphysics, COMSOL Multiphysics 5.1, https://www.comsol.de/comsol-multiphysics (last access: 14 April 2015), 2016.

    De Souza, R.: The formation of equilibrium space-charge zones at grain boundaries in the perovskite oxide SrTiO3, Phys. Chem. Chem. Phys., 11, 9939-9969, 2009.

    De Souza, R.: Oxygen Diffusion in SrTiO3 and Related Perovskite Oxides, Adv. Funct. Mater., 25, 6326-6342, 2015.

    Fergus, J. W.: Perovskite oxides for semiconductor-based gas sensors, Sensor. Actuat. B-Chem., 123, 1169-1179, 2007.

    Gerstl, M., Frömling, T., Schintlmeister, A., Hutter, H., and Fleig, J.: Measurement of 18O tracer diffusion coefficients in thin yttria stabilized zirconia films, Solid State Ionics, 184, 23-26, 2011.

    Gömann, K., Borchardt, G., Gunhold, A., Maus-Friedrichs, W., and Baumann, H.: Ti diffusion in La-doped SrTiO3 single crystals, Phys. Chem. Chem. Phys., 6, 3639-3644, 2004.

    Gömann, K., Borchardt, G., Schulz, M., Gömann, A., MausFriedrichs, W., Lesage, B., Kaïtasov, O., Hoffman-Eifert, S., and Schneller, T.: Sr diffusion in undoped and La-doped SrTiO3 single crystals under oxidizing conditions, Phys. Chem. Chem. Phys., 7, 2053-2060, 2005.

  • Metrics
    No metrics available
Share - Bookmark