Regensburg 2022 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 19: Poster 1

MA 19.46: Poster

Dienstag, 6. September 2022, 17:30–20:00, P2

THz-2D Scanning Spectroscopy — •Finn-Frederik Stiewe, Tobias Kleinke, Tristan Winkel, Ulrike Martens, Jakob Walowski, Christian Denker, and Markus Münzenberg — Institute of Physics, University Greifswald, Germany

THz-spectroscopy offers attractive imaging capabilities for scientific research, especially in life science. Its low photon energies lead to non-destructive interaction with matter In our study, we investigate THz-pulses generated by fs-laser-excitations in CoFeB/Pt heterostructures (STE), based on spin currents together with a LT-GaAs Auston switch as detector. The spatial resolution is tested by applying a 2D scanning technique with motorized stages allowing scanning steps in the sub-micrometer range. By applying an external magnetic field, the spin alignment in the CoFeB layer can be changed and the influence on the THz emission can be studied. For determining the spatial resolution, the STE is directly evaporated on a gold-test pattern separated by a several hundred nanometer thick insulating spacer layer. We observe a THz beam FWHM of 4.86 *0.37 μm at 1 THz by using near-field imaging, which are in the dimension of the laser spot [1]. Our phase sensitive detection allows to image the magnetic alignment of the CoFeB layer. For this purpose, the STE*s are patterned in micrometer sized geometric shapes on a glass substrate and scanned by our 2D scanning technique. Due to its simplicity, our technical approach offers a large potential for wide-ranging applications. [1] F.-F. Stiewe et al., Appl. Phys. Lett. 120, 32406 (2022).

Funding by: MetaZIK PlasMark-T (FKZ:03Z22C511), BMBF