Magnetism studied with circularly polarized X-rays

With the discovery of X-ray magnetic circular dichroism in the 1980s new fields were opened up for investigating the magnetism of matter. This effect is based on the dependence of the inner-shell absorption of circularly polarized X-rays emitted from synchrotron sources on the magnetic polarization of the absorbing atomic species. A large variety of methods using this phenomenon have been developed to explore the fundamentals of the magnetism of matter and the correlation between atomic magnetic characteristics and macroscopic properties. The large magnetic cross-sections allow the study of local magnetic moments separated in a unique manner into spin and orbital contributions of bulk materials, thin layers, surfaces and interfaces. In combination with X-ray microscopy techniques, magnetic nanostructures and their dynamics are addressable with 15 nm and 10 psec spatial and time resolution.