Author: Patrick Grychtol

Affiliation(s): Forschungszentrum Juelich

Coupled magnetic multilayer systems of the spin-valve type based on transition metals were fabricated by sputtering and thermal evaporation in an ultra-high vacuum. They have been investigated by reflectivity measurements of resonantly scattered p-polarized light at the synchrotron in the EUV. By employing a transversal MOKE geometry close to the Brewster angle at the M absorption edges of Co and Ni a magnetic contrast as large as 80% for Co and 20% for Ni could be obtained upon magnetization reversal. In order to map the magnitude of the dichroism, angular and energy dependent scans of the magnetic asymmetry were performed and compared with magneto-optical simulations of the multilayer response. Element-selective magneto-optical loops were recorded as a function of the interlayer thickness and reflect the switching behavior of individual ferromagnetic layers as a function of the interlayer coupling. We also observed the magneto-optical response of a multilayer system to a laser-induced magnetic pulse excitation, which results in element-specific oscillations located in a frequency range of 3GHz to 6.5GHz. This behavior can be associated with precessional magnetization dynamics of individual ferromagnetic layers. Our results demonstrate the feasibility of element-selective magneto-dynamic studies on magnetic multilayers in this spectral range. As newly developed tabletop soft X-ray sources manage to produce ultra-fast and coherent EUV pulses up to photon energies of 100eV with moderate effort, our findings pave the way for element-selective investigations of magnetic properties in heterogeneous systems on the femtosecond and nanometer scale in a laboratory environment, the former of which is currently pursued in our own optical lab.

Consider for Oral Presentation?: No