Magnetostrictive mechanical frequency combs.

Ye, Guanqi; Sun, Ruitong; Zhao, Junning; Ma, Fusheng · Nat Commun · 2025

basic_science · Level V

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Abstract

Magnetostriction plays a pivotal role in magneto-mechanical systems. Here, we propose and experimentally demonstrate a mechanical frequency comb solely requiring the fundamental mode f<sub>0</sub> of a magnetostrictive mm-scale macroresonator. Both integer-harmonic combs and half-integer-harmonic combs are observed in kHz regime with Hz resolution by near-resonant pumping f<sub>p</sub> ≈ f<sub>0</sub> and parametrical stiffness modulation f<sub>s</sub> ≪ f<sub>0</sub>. The tooth spacing of both combs is determined by f<sub>s</sub>, which can be continuously tuned by changing f<sub>s</sub> from Hz to kHz. Moreover, the half-integer-harmonic combs can be purposely switched with frequency shifting half a tooth spacing via suppressing period-doubling bifurcation. The experimentally observed formation, evolution, and switching of combs can be well understood by introducing the bias magnetical force and the parametrically modulated stiffness into the Duffing equation. Our findings could provide a magneto-mechanical platform with tunability for potential applications in the acoustic frequency range such as non-invasive/contactless sensor and wireless antenna.