The conductivity and ionic transport of doped bismuth titanate pyrochlore Bi1.6МxTi2O7−δ (М – Mg, Sc, Cu)

• Published in: Solid state ionics Vol. 302; pp. 118 - 125
• Main Authors: Krasnov, A.G., Piir, I.V., Koroleva, M.S., Sekushin, N.A., Ryabkov, Y.I., Piskaykina, M.M., Sadykov, V.A., Sadovskaya, E.M., Pelipenko, V.V., Eremeev, N.F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2017
• Subjects: Bismuth-titanates; Conductivity; Oxygen isotope exchange; Pyrochlore; Pyrochlore; Oxygen isotope exchange; Conductivity; Bismuth-titanates
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2016.12.019

Pyrochlores Mg-, Sc-, Cu-doped bismuth titanates have been obtained. The results of X-ray powder diffraction structure refinement and the pycnometric density measurement point to the preference of the dopants distribution in the A-sites of the pyrochlore structure. Electric properties were studied for single phase compounds. The mixed electron-ionic conductivity was indicated in these samples.
The high temperature (T>300°C) relaxation process was observed in Bi1.6MxTi2O7−δ at the range of frequency 103–106Hz. Oxygen mobility and surface reactivity of Bi1.6M0.2Ti2O7−δ (M – Sc, Mg and Cu) and Bi1.4Mg0.2Ti2O7−δ samples were studied by using temperature programmed isotope exchange (TPIE) with C18O2 in flow and closed reactors. According to TPIE data the regular lattice oxygen is homogeneous from the point of view of its mobility.
•The doped bismuth titanates pyrochlores Bi1.6МxTi2O7−δ (М – Mg, Sc, Cu) are mixed conductors.•The electronic type conductivity is dominated up to T=400°C and ionic conductivity is revealed at higher temperature.•The high oxygen mobility has been observed using oxygen isotope exchange method.