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arXiv · 2403.06234

Giant Nonreciprocity of Surface Acoustic Waves induced by a positive-negative magnetostrictive heterostructure

Wenbin Hu·Mingxian Huang·Yutong Wu·Yana Jia·Wen Wang·Feiming Bai
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Abstract

Lack of nonreciprocity is one of the major drawbacks of solid-state acoustic devices, which has hindered the development of microwave-frequency acoustic isolators and circulators. Here we report giant nonreciprocal transmission of shear-horizontal surface acoustic waves (SH-SAWs) on a LiTaO3 substrate coated with a negative-positive magnetostrictive bilayer structure of Ni/Ti/FeCoSiB. Although the static magnetic moments of two layers are parallel, SH-SAWs can excite optical-mode spin waves much stronger than acoustic-mode ones at relatively low frequencies via magnetoelastic coupling. The measured magnitude nonreciprocity exceeds 40 dB (or 80 dB/mm) at 2.333 GHz. In addition, maximum nonreciprocal phase accumulation reaches 188{\deg} (376{\deg}/mm), which is desired for an effective SAW circulator. Our theoretical model and calculations provide an insight into the observed phenomena and demonstrate a pathway for further improvement of nonreciprocal acoustic devices.

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Wenbin Hu, Mingxian Huang, Yutong Wu, Yana Jia, Wen Wang, Feiming Bai. 2024-03-10. Giant Nonreciprocity of Surface Acoustic Waves induced by a positive-negative magnetostrictive heterostructure. https://arxiv.org/abs/2403.06234

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