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MA: Fachverband Magnetismus

MA 21: Terahertz Spintronics

MA 21.2: Talk

Wednesday, September 7, 2022, 09:45–10:00, H43

Investigation of THz electromagnetic response in nanopatterned magnetic heterostructures by current confinement — •Bikash Das Mohapatra¹, Reza Rouzegar³, Evangelos Papaioannou¹, Tobias Kampfrath³, and Georg Schmidt^1,2 — ¹Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, D-06120 Halle, Germany — ²Interdisziplinäres Zentrum für Meterialwissenschaften, Martin-Luther-Universität Halle-Wittenberg, Heinrich-Damerow-Straße 4, D-06120 Halle, Germany — ³Department of Physical Chemistry, Fritz Haber Institute, Faradayweg 4-6, 14195 Berlin, Germany

STEs (Spintronic Terahertz Emitters) are novel THz radiation sources. Many studies have demonstrated that the STEs when illuminated with fs-laser pulse, ultrafast spin current is produced which leads to ultrafast transverse charge current by Inverse Spin Hall Effect, resulting in THz electromagnetic pulses. We were able to fabricate THz emitters into arrays of various squares and rectangles of micron or sub-micron size, using Sputter deposition and e-beam lithography. These emitters generate a different emission spectrum than large area reference emitters when irradiated with a fs laser. We propose that the confinement due to small size induces local charge buildup, which leads to additional currents that counterbalance the original charge current due to the Inverse Spin Hall Effect.