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MA: Fachverband Magnetismus

MA 46: Magnetic Measurement Methods

MA 46.2: Talk

Thursday, March 10, 2016, 15:45–16:00, H33

Incorporating Nanosecond Time Resolution into Scanning Electron Microscopy with Polarization Analysis — •Fabian Kloodt, Robert Frömter, Susanne Kuhrau, Philipp Staeck, and Hans Peter Oepen — Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg, Germany

The Scanning Electron Microscope with Polarization Analysis (SEMPA) is well established to investigate the magnetic microstructure at surfaces and in ultrathin films. Up to now only stationary measurements over several minutes of acquisition time were feasible. Our instrument is using a LEED-based spin-polarization analyzer, where the intensity of four LEED beams is monitored via single-electron counting and analyzed to calculate the magnetic contrast. Making use of modern fast electronics, the arrival time of each single electron can be determined. In this way the obtained magnetic information can be split up into distinct time slices with respect to the phase of an external periodic voltage that drives the magnetization dynamics at the sample. Results of field-driven excitations of 60nm thick FeCoSiB rectangles in the diamond state as well as squares in the Landau state will be shown and the dynamics of coupled and uncoupled vortex gyration is extracted. A temporal resolution of 700ps is achieved. The present state of the method, limitations and the development potential will be discussed.