Observation of Ferromagnetic Domains with the Scanning Electron Microscope

Abstract

It is shown that ferromagnetic domains may be observed using an unmodified scanning electron microscope. Magnetic contrast is due to the Lorentz force acting upon secondary electrons as they pass through magnetic fields near the surface of the sample. The influence of these fields is more marked upon secondary electrons of lower energy, and only these slower electrons contribute significantly to magnetic contrast. The technique described depends upon mounting the specimen in a position such that a straight line between the area under study and the collector is intercepted by a shield or by the bulk of the sample, in order to prevent many of the faster secondary electrons from contributing to the image.