Diffuse Scattering in FeOF

Typical <013> and <110) zone axis EDPs of rutile type FeOF. The presence of a characteristic diffuse intensity distribution in the form of continuous rods of diffuse intensity running along both the [110]* and [1-10]* directions of reciprocal space through the (h + k + l) = odd parent rutile reflections can be seen in the <013> pattern (left). The ends of these rods can be seen as additional reflections between the parent rutile spots in the <110> type pattern (right). It is the Fe3+ shifts induced by local O/F ordering which are responsible for intensity distribution of this observed diffuse scattering. The continuous <110>* rods of diffuse intensity require the existence of orthogonal {110} planes within the parent rutile structure which exhibit long range, two-dimensional, oxygen/fluorine ordering, but with no correlation from one {110} plane to the next.

Image provided by Frank Brink (ANUEMU)