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MA: Fachverband Magnetismus

MA 20: Magnonics II

MA 20.5: Vortrag

Mittwoch, 19. März 2025, 10:30–10:45, H16

SAW-Induced Spin Wave Excitation in Ferromagnetic Epitaxial Thin Films — •Alfons Georg Schuck, Sebastian Kölsch, and Michael Huth — Institute of Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany

Surface acoustic wave (SAW) excitation of spin waves in ferromagnetic thin films has recently gained significance due to the potential for the realization of novel microwave devices and applications in magnonics. So far, SAW excitation has commonly been accomplished by use of piezoelectric substrate materials, such as LiNbO₃, on top of which the ferromagnetic thin film is deposited [1]. This approach has severe limitations with regard to studying SAW-spin wave coupling effects in epitaxial magnetic thin films. For epitaxy to occur, selected substrate materials and crystal orientations have to be used; and these substrate materials tend not to be piezoelectric.

Here we show how textured piezoelectric AlN thin film transducer structures can be fabricated on different substrate materials by means of reactive RF sputtering. By proper selection of the material for the interdigital transducer electrode structures and standard UV lithography, the frequency range up to about 3 GHz becomes available for spin wave excitation. Selected examples of SAW-induced spin wave excitation in epitaxial magnetic thin films are presented and compared to results obtained on Nickel thin films as commonly used reference material. Complementary simulations of the SAW attenuation are shown and the influence of the magnetic anisotropy is described.

[1] M. Weiler et. al., Phys. Rev. Lett. 106, 117601, 2011

Keywords: Surface Acoustic Waves; Magnons; Spin Waves; Thin Films