Lattice fringe images obtained with a high resolution electron microscope have been used to investigate the periodic variation of lattice spacing associated with the spinodal decomposition of some alloys. It is shown that the variation of fringe spacing seen in the image can exceed the actual variation of lattice fringe spacing in the specimen by a large factor as a result of phase variations associated with the transfer function of the objective lens. This modification of the fringe spacing is minimized, although not eliminated, for a particular value of the objective lens defocus.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics