A neutron diffraction study of the oxygen diffusion in molybdenum doped Ba2In2O5

作者：Rolle Aurelie^*; Roussel Pascal; Giridharan Nambi Venkatesan; Suard Emmanuelle; Vannier Rose Noelle

来源：Solid State Ionics, 2008, 179(35-36): 1986-1995.

DOI：10.1016/j.ssi.2008.06.021

• Barium oxide
• Indium oxide
• Brownmillerite
• Oxide ion conductor
• Neutron diffraction
• X-ray diffraction
• Anharmonic model

The structures of molybdenum doped Ba2In2O5 were refined using X-ray and neutron diffraction data at room and high temperature with the aim to derive preferred oxygen diffusion pathways. At room temperature, refinement of composition Ba2In2-xMoxO5+3x/2 with x=0.1 revealed that molybdenum atoms are preferentially located in the tetrahedral layers of the brownmillerite. At 700 degrees C, the structure can be viewed as the stacking of alternating In and In/Mo octahedral layers. The conduction process occurs preferentially in the latter which is highly oxygen deficient. Preferred oxygen diffusion pathways were deduced from joint Probability Density JPDF) and energy barriers were derived. It was in good agreement with the activation energy deduced from impedance spectroscopy for composition x=0.1 at 950 degrees C. However, calculation of energy barrier assumes a dynamic disorder of oxide ions which is unlikely to occur at lower temperature and for sample containing a larger amount of molybdenum. Composition x=0.5 is cubic on the whole range of temperature. At room temperature, JPDF revealed a static disorder of the oxygen atoms, which is likely due to the solution of molybdenum into the barium indium perovskite. When temperature increases the disorder becomes more and more dynamic.

• 出版日期2008-10-31