Berlin 2024 – scientific programme

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MA: Fachverband Magnetismus

MA 20: Poster I

MA 20.4: Poster

Tuesday, March 19, 2024, 16:30–19:00, Poster A

Wide-band nonreciprocal transmission of surface acoustic waves — •Stephan Glamsch, Matthias Küß, Andreas Hörner, and Manfred Albrecht — Institute of Physics, University of Augsburg, 86135 Augsburg, Germany

Surface acoustic waves (SAWs) are utilized in everyday devices as rf-filters and sensors. However, SAWs are in general propagating reciprocally, which means that the acoustic wave properties do not change under an inversion of the propagation direction. Resonantly coupled to spin waves (SWs) in a magnetic material, the SAW transmission can instead become nonreciprocal, which holds potential for novel microwave devices, e.g. acoustic diodes. Large nonreciprocal SAW transmission in a limited frequency range close to the punctual intersection of SAW and SW dispersions have been recently demonstrated [1]. Nevertheless, nonreciprocal SAW transmission over a wide frequency band has only been theoretically predicted until now [2]. In our most recent work, we show the first experimental demonstration of a wide-band nonreciprocal SAW transmission. For that, we adjusted the SW dispersion of a CoFeB/Ru/CoFeB synthetic antiferromagnet (SAF) to match the linear dispersion of the SAW over a frequency range of 2.8 GHz < f < 7.0 GHz. Therefore, a low loss (< 0.08 dB) mediated by SAW-SW interaction in the forward direction and large attenuation (> 5dB) in the reverse direction has been achieved.
[1] M. Küß et al., ACS Appl. Electron. Mater. 5, 5103 (2023).
[2] R. Verba et al., Phys. Rev. Appl. 12, 054061 (2019).

Keywords: Nonreciprocity; Surface acoustic waves; Spin waves; Synthetic Antiferromagnet; Magnetoacoustic