MAGNETIC ELECTRON-EMISSION HOLOGRAPHY

In the recently developed technique of electron emission holography, t he sources are electron emitting atoms, adsorbed on the surface or par t of the substrate. The directly emitted electron serves as a referenc e wave and its interference with the elastically scattered wave is res ponsible for the hologram character of the angular resolved intensity pattern. A straightforward numerical transform of this pattern yields a holographic ''image'' of the emitter's environment on the atomic sca le. We show that the effect of exchange on the electron scattering pro cess similarly allows imaging of the nearby magnetic environment from the angular resolved electron spin polarization pattern, the spin holo gram. In the proposed experiment, the electrons are assumed to be emit ted from inner-core levels in an unpolarized manner. Consequently, any atom, magnetic or not, can be used as a source. The transform of the spin hologram then gives a picture of the spin vectors of the neighbor ing atoms. This suggests a broad range of experimental applications in the field of surface magnetism, ranging from anisotropy to antiferrom agnetically coupled layers. We present the physics of the method and d iscuss briefly potential problems, such as the influence of multiple s cattering and self-imaging. To illustrate the technique, we present th e results of model calculations.