On Determination of the Double‐Force Tensor of Point Defects in Cubic Crystals by Diffuse X‐Ray Scattering

Abstract

Abstract A systematic method is described for determining the double‐force tensor of point defects in cubic crystals by analysing diffuse X‐ray scattering in the immediate vicinity of Bragg reflections (Huang‐scattering). Around a given reciprocal lattice point there may occur three types of isointensity surfaces depending on the symmetry of the defects: the “double‐drop” type (“lemniscatoidal” with two sheets), the “apple‐shaped” type (“lemniscatoidal” with one sheet) and the “single‐bubble” type (“ellipsoidal”). The double‐force tensor of point defects can be determined uniquely from Huang scattering if the defects are all equal and parallel . If the orientations of the defects are randomly distributed over equivalent directions of the lattice, information obtained from scattering intensity allows several double‐force tensors. In this case even three selected points of the reciprocal lattice are sufficient to present all of the information which Huang scattering can give about the structure of the defects.