Butterfly-shaped FeGa film/AT-cut quartz wafer double-sided composite resonant magnetic field sensor
Due to magnetic convergence,the magnetostrictive strain in the central region of a butterfly-shaped magnetostrictive film is enhanced.However,when the butterfly-shaped magnetostrictive films are combined with the rectangular AT-cut quartz wafer,the strain in the electrode region of the rectangular wafer spreads out to the surrounding non-magnetic film region and thus reduces the effect of the strain on the thickness-shear vibration of the wafer and consequently reduces the sensitivity of magnetic field sensor.In this paper,a butterfly-shaped resonant magnetic field sensor with the same shape of AT-cut quartz wafer as the FeGa films sandwiching the wafer is proposed.The butterfly-shaped sandwiched composite can concentrate the strain enhanced by the butterfly-shaped film into the electrode region of the wafer to improve the sensor sensitivity.The simulation results predict that the sensitivity of the butterfly-shaped structure is 3.73 times that of the butterfly-shaped magnetic film/rectangular wafer structure.By MEMS fabrication,we developed the butterfly-shaped sensor,and the characterization of the actual device shows that the sensitivity can reach-29.08 Hz/Oe in the linear range of 76.4～117 Oe.
resonant magnetic field sensorAT-cut quartz crystalFeGa filmbutterfly-shaped structure
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