Dresden 2014 – wissenschaftliches Programm
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AGjDPG: Arbeitsgruppe junge DPG
AGjDPG 2: PhD Symposium: Magnon Plasmonics (jointly with MA)
AGjDPG 2.3: Vortrag
Dienstag, 1. April 2014, 10:45–11:00, HSZ 04
Plasmonic excitations in permalloy wires imaged by XPEEM — •Ahmet Akin Ünal1, Judith Kimling2, Sergio Valencia1, and Florian Kronast1 — 1Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany — 2Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung Hamburg, Universität Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
We investigate the influence of surface plasmon resonances in laser-excited gold nanoantennas on the demagnetization of neighboring magnetic microstructures. At metal surfaces, electromagnetic waves and light waves can couple with each other, forming surface plasmons (SP). A gold nanoantenna can be regarded as a resonator for SPs. In the case of resonant excitation, the oscillation amplitudes of the plasmon waves can overcome the excitation amplitude by orders of magnitude giving rise to a strong enhancement of the local electromagnetic field. Here, we investigate this local field effect of the plasmonic antennas on the neighboring permalloy microstructures, specifically on their magnetization dynamics. Permalloy (Ni0.81Fe0.19) microstructures and gold antennas were prepared by e-beam lithography on a Si(110) substrate. We studied the switching as function of laser polarization and power and we find that the laser power threshold, above which switching occurs, is much lower for structures with antennas than for reference structures without antennas next to them. This allows us to quantify the effect of the plasmonic antennas in each structure and compare it to plasmonic wave fields imaged by PEEM.