Measurement of magnetic fields and domain structures using a photoemission electron microscope

The technique of photoemission electron microscope (PEEM) allows observation of the domain boundaries on ferromagnetic surfaces arising from magnetic stray fields at definite conditions. In most cases a very weak contrast due to the Lorentz force is formed, which can be measured by the use of digital methods of signal registration and data processing. If the electron beam is restricted by either an aperture diaphragm or a knife-edge being located in the crossover plane, the sensitivity of PEEM to the magnetic fields is strongly enhanced. This permits comparatively weak stray fields of the domain boundaries to be observed. However, it is necessary to use a special microscope construction for this method of observation. An aperture diaphragm or a knife-edge should be placed in the crossover plane of the immersion lens. In the case of excitation using circularly polarized radiation it is possible to exploit magnetic x-ray circular dichroism (MXCD) for contrast formation. This contrast arises as a consequence of optical spin orientation.