Emission of Polarized Electrons from Solids

Abstract

This chapter focuses on the physical properties of solids and the nature of the electron emission process. In all types of photoemission experiments, some common problems have to be overcome. The distinguishing characteristic in spin-polarized photoemission is that the emitted electrons are collimated to form a beam that is directed onto a polarization detector, in this chapter it is based on Mott scattering. The main results obtained so far are concerned with establishing the energy order of magnetic and nonmagnetic electron states, obtaining information on magnetism of surfaces and magnetic proximity effects, and getting some insight into the electron states in the critical but interesting intermediate range where neither the band model nor the atomic picture is the correct approach. As to 3d magnetic materials, it has been seen that the electronic excitations in magnetite and other ferrites must be explained by the model of a single ion in a crystal field. Photoelectron spin polarization (ESP) shows unambiguously that there is little relation between initial band density of states and photoemission, and optical absorption data.