The coupling of single crystal diamond (SCD) micro-electromechanical systems (MEMS) through with a functional hetero-material provides the strategy to develop diamond MEMS sensors. Here a noncontact magnetic sensor based on SCD MEMS resonance system functionalized with a boron-doped FeGa (FeGaB) thin film owning excellent magneto-strictive properties on diamond is demonstrated to improve the magnetic sensitivity. The amorphous FeGaB thin film is beneficial for high magnetic sensing performance. The FeGaB/Ti/SCD MEMS magnetic sensor exhibits magnetic sensitivity of as high as 152.1 Hz/mT, which is over four times of those of FeGa/Ti/SCD MEMS magnetic sensors. The derivative of the Young's modulus change with magnetic field (dE/dH) reaches a maximum value of 4.5 GPa/mT at 1.77 mT. By tailoring the magnetic properties with impurity dopant, one can markedly improve the sensitivity of the diamond MEMS magnetic sensitivity toward satisfying the figure-of-merits of ultra-high sensitivity, low noise level and high-reliability magnetic field operation.
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