Lorentz electron microscopy of domain walls in single−crystal evaporated iron films

A method for measuring the width of domain walls by Lorentz electron microscopy is presented and applied to the case of a single−crystal iron film. The method consists of measuring the domain wall image width at a number of defocusing distances and fitting the resulting curve to a theoretical curve of image width versus defocusing distance using the wall width and a parameter which is a function of the deviation of the beam as variables. The appearance of the wall images and the measured wall widths indicate that domain walls in single−crystal iron films around 1000 Å thick are 180 ° asymmetric and 90 ° symmetric or asymmetric types.