The Outer Fringe of a Stacking Fault

Abstract

The rule of Hashimoto, Howie, and Whelan, much used in electron microscopy for determining the nature of stacking faults, is known to be true when the specimen thickness t is sufficiently great. It is shown that sufficiently great means that the product (t;gg)(gglg~) must be greater than 0·2 for bright field or greater than O· 25 for dark field, these values being for reasonable deviations from the Bragg condition.