Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 46: Magnonics II
MA 46.2: Vortrag
Donnerstag, 15. März 2018, 15:30–15:45, H 0110
Tunable short-wavelength spin wave emission and confinement in anisotropy-modulated multiferroic heterostructures — Sampo J. Hämäläinen1, Florian Brandl2, Ben Van de Wiele3, Kévin J. A. Franke1, Dirk Grundler2, and •Sebastiaan van Dijken1 — 1Department of Applied Physics, Aalto University, Finland — 2Institute of Materials, EPFL, Switzerland — 3Department of Electrical Energy, Ghent University, Belgium
Excitation of short-wavelength spin waves from a precise location is essential for the downscaling of magnonic devices. Here, we report on the generation and confinement of short-wavelength spin waves in a continuous film with periodically modulated magnetic anisotropy. The concept, which is demonstrated for strain-coupled CoFeB/BaTiO3 heterostructures, relies on abrupt rotation of magnetic anisotropy at the boundaries of magnetic stripe domains. In combination with an external bias field, this produces a lateral variation of the effective magnetic field, leading to local spin wave excitation when irradiated by a microwave magnetic field. In domains with small effective field, spin waves are perfectly confined by the spin gap in neighboring domains. In contrast, standing spin waves in domains with large effective field radiate into neighboring domains. Using micromagnetic simulations, we show that the wavelength of emitted spin waves is tunable from a few micrometers down to about 100 nm by rotation of the bias field. We also demonstrate that dynamic fluctuations of the effective magnetic field and microwave spin-polarized currents can be used to excite exchange-dominated spin waves in multiferroic heterostructures.