Spin-resolved photoemission of thin magnetic films

Magnetic properties of thin films offer a fascinating field of research. Besides the fundamental interest in physical properties, such as the magnetic moment, the Curie temperature and the dependence of the magnetization on temperature or film thickness, magnetic materials are also technically important. The understanding of ferromagnetism and the electronic structure of ferromagnets are a first step in the development of new data storage devices. To study the electronic structure of ultrathin films in the monolayer regime, it is important to use a surface sensitive experimental technique. Electrons are very well suited as a carrier of information, due to their small inelastic mean free path (IMFP) in solids. For energies in the range of 10-1000eV the IMFP of electrons is typically below 20$\mathring{A}$ (see fig. 1.1). [...] Fig. 1.1: Universal Curve of electron mean free path, after {Zangwill, 88]. Theory by Penn [Penn, 76] One of the most common techniques using electrons as a sample probe is photoelectron spectroscopy. Photons of a specific energy are absorbed by electrons in the sample. Energy conservation demands that the excited system takes the energy of the annihilated photon as a whole. If the energy of the excited electrons is high enough to overcome the work function they can be detected outside the sample and characterized with respect to their kinetic energy, momentum and spin