Materials-science applications of novel methods for the analysis of electron-diffraction patterns

Abstract

Electron diffraction provides a highly effective method for the identification of microscopic, crystalline phases in the solid state. The following examples are given to illustrate applications of three new analytical methods to typical problems in analytical microscopy of materials.Phase identification using convergent beam electron diffraction (CBED) patterns can often be simplified when measurements from the zero and high order Laue zones (ZOLZ and HOLZ) are combined to calculate the primitive cell volume, Vc. Defining g1 and g2 as two primitive vectors in the ZOLZ (e.g. two non-collinear spots closest to the transmitted beam) the volume of the primitive reciprocal cell is;Vc* = g1 × g2 . H,where H is the reciprocal interplanar spacing calculated from the diameter(s) of the HOLZ ring(s). This calculation can be performed without indexing the pattern. The inverse of Vc* is the volume of the primitive cell, Vc, which is easily compared with literature data for possible phases.