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CBED patterns present the deficiency lines in the zero-order disc, which result from excitation of reflections in higher order Laue zones (HOLZ) and are called HOLZ lines. Unlike SAD patterns, CBED ZAPs contain three-dimensional (3D) information, due to the enhanced HOLZ signatures.
The positions of the HOLZ lines are related to the symmetry and lattice parameters of the crystal. They are changed in the direction of the applied stress if the material is stressed and those changes induce a change in the Bragg condition and thus a shift of the HOLZ lines. By analyzing their positions in combination with a reference CBED patern, a quantitative analysis of the three-dimensional (3-D) strain state of the crystal can be accurately performed.
In order to obtain the HOLZ rings in intensity, the magnification of the diffraction pattern should be small enough and the convergence angle should be large enough. These rings state that diffraction has occurred from other layers of the reciprocal lattice.
With a small camera length, the HOLZ rings can be recorded using CBED technique. Note that energy filtering enhances HOLZ line contrast in CBED and enables us to study the HOLZ patterns from a thick specimen.
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