Berlin 2024 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 16: Magnonics I
MA 16.10: Vortrag
Dienstag, 19. März 2024, 12:00–12:15, EB 107
Giant Surface Acoustic Wave Nonreciprocity in CoFeB/Ru/CoFeB Synthetic Antiferromagnets — •Matthias Küß1, Stephan Glamsch1, Mariam Hassan1, Yannik Kunz1, Andreas Hörner1, Mathias Weiler2, and Manfred Albrecht1 — 1Institute of Physics, University of Augsburg, 86135 Augsburg, Germany — 2Fachbereich Physik and Landesforschungszentrum OPTIMAS, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
Surface acoustic waves (SAWs) have made their way into many everyday devices. These "nano earthquakes" can be efficiently launched and detected on piezoelectric substrates with periodic metallic gratings. Resonant coupling of SAWs with spin waves (SWs) is the basis for an energy-efficient approach towards SW manipulation. In addition, magnetoacoustic interaction affects the properties of the SAW, which in turn can be used to devise new types of microwave devices.
Here, we investigate the SAW-SW interaction in a synthetic antiferromagnet (SAF) composed of two ferromagnetic layers separated by a thin nonmagnetic spacer layer. The low-frequency SW mode shows a large nonreciprocal SW dispersion f(+k) ≠ f(−k). Because of efficient coupling between this SW mode and the SAW, we observe large nonreciprocal SAW transmission in the piezoelectric/SAF hybrid device. We demonstrate that the SAW transmission nonreciprocity can be optimized to be giant (>100 dB) in CoFeB/Ru/CoFeB SAFs made out of low-damping CoFeB magnetostrictive layers, which holds potential for the realization of acoustic isolators [M. Küß et al., ACS Appl. Electron. Mater. 5, 5103 (2023)].
Keywords: Spin Waves; Magnetoacoustics; Surface Acoustic Waves; Nonreciprocity; Synthetic Antiferromagnet