Low energy electron microscopy (LEEM) and photo-emission electron microscopy (PEEM) have been widely considered as powerful methods of real time observation with versatile functionality and high lateral resolution required for the dynamic measurements of surfaces and interfaces. Spin-polarized LEEM (SPLEEM), which is mainly described in this article, has a spin-polarized electron gun (spin gun) and makes detailed magnetic domain observation possible. We developed the spin gun having very high brightness, high spin-polarization and long life time which enabled us to conduct the dynamic imaging of magnetic domains as well. We adopted several innovative ideas to develop the high performance spin gun, e.g., the backside illumination of laser beam to a photo-cathode for high brightness, strained super lattices of GaAs/GaAsP for high spin-polarization and extremely high vacuum for long life time of photo-cathodes. Such novel SPLEEM has been applied to [CoNix]y system, one of the promising multi-layered materials for spintronics devices.
