Physics Seminar
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  • Physics Seminar

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Magneto-plasmonic excitations in permalloy microstructures imaged by XPEEM

We investigate the infuence of surface plasmon resonances in laser-excited gold nanoantennas on the demagnetization of neighboring magnetic microstructures. At metal-dielectric interfaces, surface plasmon (SP) modes can be excited by the coupling of light with conduction band electrons. A gold nanoantenna can be regarded as a resonator for localized SPs. Here, we investigate the local fıeld effects of the plasmonic antennas on the neighboring permalloy microstructures, specically on their magnetization dynamics. We studied magnetization switching as function of laser polarization and fluence, and we found that localized plasmons of the antennas can change and control the magnetization of the neighboring structures. Additionally we observed propagating plasmonic wave fıelds, which were successfully imaged by the x-ray photoemission electron microscope (XPEEM).

Short bio:
Ahmet Akın Ünal studied Physics at Koc University, 2003, and did his M.Sc. at Sabanci University, 2005. In June 2009 he received his PhD degree in Physics from Max-Planck-Institute (MPI) of Microstructure Physics and Martin-Luther-University in Halle, Germany, where he investigated structural modification dynamics of plasmonic nanoparticles using time-resolved optical spectroscopy. Afterwards he was a postdoctoral researcher at MPI for 2,5 years, investigating electronic structure of surfaces via photoemission experiments. Since 2012, he has been working as a postdoc researcher at the synchrotron radiation facility of the Helmholtz-Zentrum Berlin. His research areas comprise a variety of interdisciplinary subjects including optics, plasmonics, magnetism and surface science and are based on experiments using ultrashort-pulsed lasers and x-ray light sources.