Local ordering of oxygen vacancies in cubic zirconia stabilized with yttria and magnesia .2. Determination of local ordering parameters of oxygen vacancies

Diffuse scattering produced by oxygen-vacancy local ordering in ZrO2 stabilized by Y2O3 and MgO was studied by Dai er al. in 1996 using electron diffraction. A three-dimensional geometrical model in reciprocal space was established for describing the equal intensity contours of diffuse scattering observed experimentally. In this paper, the kinematical electron diffraction theory is applied to calculate the diffuse scattering produced by oxygen vacancies. A direct relationship between the local ordering parameters and the distribution of diffuse scattering intensity is given. By assuming that the intensity profile across the maximum intensity contour, as defined by the surface of the geometrical model, is a Gaussian shape, the local ordering parameters of oxygen vacancies are determined. The parameters are then reapplied to calculate the distribution of diffuse scattering intensity, and the results show good agreement with the experimental observations. It is concluded that the oxygen vacancy-oxygen vacancy is preferably linked by the r([200]) and r([310]) position vectors of the anionic sublattice (a/2, b/2, c/2) of fee fluorite structure (a, b, c) and oxygen-anion-oxygen vacancy is preferably linked by r([110]), r([211]) and r([220]).