The application of iterative techniques to the investigation of strong phase objects in the electron microscope

Abstract

Iterative procedures are used to determine the phase distribution, and hence variation of average flux density, from the low-angle electron diffraction patterns from three different periodic magnetic structures, weak and strong stripe domains in evaporated permalloy films and stripe domains in a single-crystal cobalt foil. The peak-to-peak variations in phase are found to be 3, 35 and 32 radian, respectively, and sensible phase solutions for the latter two cases are obtained by initially assuming the phase variation to be sinusoidal. The flux density distributions deduced here are in good agreement with theoretical calculations and with results obtained by other experimental techniques. Some advantages accruing from the use of the present technique are discussed.