Experimental Investigations of Surface Magnetism

摘要

Chapter 1 gives a short account of the historical development in the experimental and theoretical understanding of the phenomena associated with magnetism, as well as a survey of some important experimental techniques that can be applied to investigate these phenomena, mainly from a spectroscopists view. Chapter 2 describes the implementation of a novel technique, namely BISCEPS: bremsstrahlung isochromat spectroscopy combined with electrons with polarized spin, designed to study the unoccupied electronic states of magnetic materials. Next to the occupied states, the unoccupied states are also important for the physical properties of magnetic materials. In Chapter 3 two applications of BISCEPS are presented. The spin-resolved unoccupied states of the elemental ferromagnet nickel have been studied at room temperature. These measurements demonstrate the feasibility of BISCEPS. Another application, which is still at present in progress, is the determination of the magnetic coupling between thin ferromagnetic gadolinium overlayers and a nickel substrate at low temperature. The temperature dependence of the electronic structure of magnetic systems is the subject of Chapter 4. Finally, in Appendix A, measurements are reported with a surface-enhanced implementation of Mossbauer spectroscopy, the 30 years old technique that has had such a large impact on the field of magnetism.