Freie Universität Berlin     Fachbereich Physik     Wolfgang Kuch: Research projects (work done at Max-Planck-Institut für Mikrostukturphysik, Halle)

Magnetic imaging by photoelectron emission microscopy (PEEM)       Magnetic circular dichroism (XMCD) Magnetization reversal in magnetic microstructures Spin-reorientation transitions Bilayers of antiferromagnetic and ferromagnetic films Layer-resolved magnetic microscopy Microspectroscopy: Fermi surface mapping Microspectroscopy: magnetic contrast from photoemission Time-resolved magnetic domain imaging

(the PEEM at work)

See also: Research topics of AG Kuch at Freie Universität Berlin

See photographs of the previous group at MPI Halle

Magnetic circular dichroism (XMCD)...    ...is used as element-selective magnetic contrast mechanism for the magnetic imaging in PEEM. XMCD is the dependence of x-ray absorption on sample magnetization direction. More...

Magnetization reversal in magnetic microstructures    The magnetization reversal of magnetic microstructures can be followed with the PEEM by applying short magnetic field pulses between the acquisition of domain images. Interesting domain configurations are observed in triangular microstructures. More...

Spin-reorientation transitions...    ...are changes in the preferred direction of magnetization from perpendicular to the film plane (out-of-plane) to in-plane as a function of film thickness, temperature or composition. Close to spin-reorientation transitions typical magnetic domain patterns, characterized by a branching into smaller and smaller stripe domains, are frequently observed. More...

Bilayers of antiferromagnetic and ferromagnetic films    The magnetic coupling at the interface between an antiferromagnetic and a ferromagnetic layer is  of highest fundamental and technological importance due to the phenomena encountered ("Exchange Bias"). Single crystalline bilayers of Co (ferromagnet) and FeMn (antiferromagnet) can be grown on Cu(001). Magnetic imaging revealed stunning changes in the as-grown domain patterns when at the paramagnetic/antiferromagnetic transition of the FeMn layer. More...

Layer-resolved magnetic microscopy    Taking advantage of the element-selectivity of the method, different magnetic layers in a multi-layered magnetic sample can be imaged separately at the same position. This allows to identify micromagnetic mechanisms coupling two magnetic layers that are separated by a non-magnetic spacer layer. More...

Microspectroscopy: Fermi surface mapping    The PEEM can not only be used to display magnified images of the sample surface.  When the projection lenses are set to display the focal plane of the objective lens, the angular distribution of the emitted electrons is obtained.  This can be used to display two-dimensional photoelectron angular distribution patterns and perform, for example, Fermi surface mapping. More...

Microspectroscopy: Magnetic contrast from photoemission    When energy filtering of the imaged electrons can be performed, additional  contrast mechanisms besides XMCD can be used for magnetic imaging. Magnetic contrast can be obtained taking advantage of magnetic dichroisms in angle resolved photoelectron spectroscopy. More...

Time-resolved magnetic domain imaging    Stroboscopic time-resolved measurements can be performed by synchronising short magnetic field pulses to the time structure of the synchrotron radiation, which is delivered in short pulses. We present the first time and layer resolved magnetic imaging studies of magnetization reversal dynamics, using trilayered magnetic spin-valve systems as samples. More...

E-mail comments and questions to kuch@physik.fu-berlin.de.

Last update: 28-Aug-2003                        back to top