On Forbidden Reflection Spots and Unexpected Streaks Appearing in Electron Diffraction Patterns from Hexagonal Cobalt

Abstract

Using thin sections of hexagonal cobalt, the origin of the appearance of some of forbidden reflection spots and some of unexpected streaks has been studied by the selected area diffraction technique. The former spots are forbidden by the space group symmetry and the latter streaks are unexpected from stacking faults. The experimental results lead to the conclusion that the reflection spots in question which are forbidden also dynamically in the symmetrical case are observed because of bending of a specimen film and the streaks in question are caused by the dynamical interaction of other streaks due to stacking faults and normal reflections.