IMAGING MAGNETIC DOMAINS WITH THE X-RAY DICHROISM PHOTOEMISSION MICROSCOPE

Few techniques are available to create images of magnetic domain structures at surfaces, due to the weakness of magnetic forces and the relative inefficiency of electron spin-detectors. We have introduced a new method for high-resolution mapping of magnetic domains, that measures the local magnetic moment and magnetization direction of individual elemental constituents of the sample. In addition, it is able to probe the magnetic properties of layers buried as much as 100 angstrom below the surface. The method uses the magnetic X-ray dichroism effect, in combination with the X-ray photoelectron emission microscope (X-PEEM), also called the X-ray secondary-electron microscope (XSEM). The principles involved in imaging magnetic domains using an X-ray photoelectron emission microscope are discussed, based on recent results using circularly polarized soft X-rays. Examples of applications of the technique include direct mapping of the oscillatory exchange coupling in transition metal sandwich structures, and imaging of recorded bit patterns in magnetic media. New results from perpendicular recording media are presented.