Magnetoactive acoustic metamaterials based on nanoparticle-enhanced diaphragm

Xingwei Tang; Shanjun Liang; Yusheng Jiang; Cong Gao; Yujin Huang; Yuan Zhang; Chang Xue; Weijia Wen

doi:10.1038/s41598-021-01569-9

Magnetoactive acoustic metamaterials based on nanoparticle-enhanced diaphragm

Sci Rep. 2021 Nov 12;11(1):22162. doi: 10.1038/s41598-021-01569-9.

Authors

Xingwei Tang¹, Shanjun Liang², Yusheng Jiang³, Cong Gao⁴, Yujin Huang⁵, Yuan Zhang⁶, Chang Xue⁶, Weijia Wen^{7

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Affiliations

¹ Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
² Division of Science, Engineering and Health Studies, College of Professional and Continuing Education, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, SAR, China.
³ College of Communication Engineering, Chongqing University, Chongqing, 400044, China.
⁴ Advanced Materials Thrust, The Hong Kong University of Science and Technology, Guangzhou, Guangdong, China.
⁵ Shenzhen Fantwave Tech. Co., Ltd, Shenzhen, 518110, China.
⁶ Materials Genome Institute, Shanghai University, Shanghai, 200444, China.
⁷ Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. phwen@ust.hk.
⁸ Advanced Materials Thrust, The Hong Kong University of Science and Technology, Guangzhou, Guangdong, China. phwen@ust.hk.
⁹ HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Futian, Shenzhen, China. phwen@ust.hk.

Abstract

Magnetoactive membrane-type acoustic metamaterials are fabricated by coating a layer of magnetic nanoparticles on the polyethylene (PE) membranes and their vibration characters are investigated experimentally. From our experiments, we discovered that, under different magnetic fields by varying the distance between a magnet and the membranes, such membranes exhibit tunable vibration eigenfrequencies (the shift towards lower frequencies), which is caused by the variation of the effective mass density and effective tension coefficient resulted from the second derivative of the magnetic field. The strong magnetic force between the layer of magnetic nanoparticles and the magnet enhances the eigenfrequency shift. A spring oscillator model is proposed and it agrees well with the experimental results. We also experimentally observed that the vibration radius, effective mass density, and effective tension coefficient of the membranes can enormously affect the eigenfrequencies of the membranes. We believe that this type of metamaterials may open up some potential applications for acoustic devices with turntable vibration properties.