Resonant magnetic scattering studies using synchrotron radiation and laser-generated extreme ultraviolet light
Autori
Viac o knihe
In this thesis magnetic domain patterns of ferromagnetic alloys are studied using resonant magnetic scattering (RMS). For this purpose synchrotron radiation in the soft X-ray range and laser-based extreme ultraviolet (XUV) light from a laboratory light source are employed. The synchrotron measurements give detailed information about the properties of magnetic domains with nanometer precision and element selectivity. These specialties allow investigations of domain patterns of complex layered systems, including FePd/CoPd bilayers or CoPd/Pd/NiFe trilayers. Time-resolved experiments with visible laser radiation are conducted to examine the laserinduced demagnetization of FePd/CoPd bilayers, pointing out the in uence of intense laser pulses on the magnetic coupling of the two layers. This technique is capable of tracing the temporal evolution of the magnetization, nevertheless it cannot image nanometer-sized magnetic domains due to the limited spatial resolution. Consequently, a new approach is necessary to resolve domain patterns and ultrafast magnetization dynamics at the same time. This aim motivates the most important question addressed in this thesis: whether a tabletop XUV light source based on high-order harmonic generation (HHG) can be used for RMS experiments on magnetic domain patterns. In this context it is further shown, how intense laser exposure causes permanent and reversible modications of the magnetic nanostructure and the sample morphology. Finally, coherence properties of the generated XUV radiation are examined, using nonmagnetic scattering at grains and knife-edge diraction. The results obtained reveal the advantages and limitations of HHG sources for applications which demand a high light coherence.