Magnetic transmission X-ray microscopy: Imaging magnetic domains via the X-ray magnetic circular dichroism

X-ray magnetic circular dichroism (X-MCD), i.e. the dependence of the absorption of circularly polarized X-rays on the magnetization of a ferromagnetic sample used as a contrast mechanism in combination with a high resolution transmission X-ray microscope (TXM) enables a quantitative and element-specific imaging of magnetic structures with a lateral resolution down to about 30 nm. Quantitative information on the local magnetization can be obtained, in particular a separation between spin and orbital moments is possible by applying magneto-optical sum-rules. Images in varying external magnetic fields can be recorded and allow to study magnetization reversal processes within a complete magnetization cycle. Multilayered systems of FeGd and PtCo have been studied. Results on the mechanism of pinning of domain walls as, e.g. the density of pinning centers are presented.