COHERENT FOUCAULT IMAGING - A METHOD FOR IMAGING MAGNETIC DOMAIN-STRUCTURES IN THIN-FILMS

A method for imaging magnetic domain structures in the transmission el ectron microscope is described. Coherent Foucault imaging provides a d irect means of producing a magnetic interferogram which reveals the qu antitative distribution of magnetic induction across the specimen. The technique requires the high coherence of a field-emission gun system and the ability to position an aperture accurately to cut part of the diffraction pattern. A simple analytical theory, together with compute r simulations and experimental results, is presented to demonstrate th e power of the technique.