Abstract
Spin-polarized electron sources have important applications in electron spectroscopies that provide insight into the electronic structure of magnetic materials. A spin-polarized electron gun, based on photoemission from a GaAs cathode, has been designed for spin-polarized inverse photoemission and spin-polarized electron scattering. Our spin-polarized electron source is used in combination with a Geiger-Mueller isochromat photon detector (for inverse photoemission), a small electron energy analyzer for electron spin scattering, and a pulsed magnetic field to saturate the magnetization of the sample. Such sources must have very stable emission, well-defined electron polarization, and excellent focus for spectroscopy applications. Much of this depends on a stable laser and associated optical systems in the near-IR. The geometry of the incident circularly polarized light with respect to the direction of electron emission, as well as the electron optics, are designed so that the electron spin polarization is consistently in the plane of the sample for any incident angle in angle-resolved measurements for electron wave-vector-dependent studies. We provide examples of the types of novel measurements possible with such instrumentation. (Author)