On‐chip Diamond MEMS Magnetic Sensing through Multifunctionalized Magnetostrictive Thin Film

Abstract Electrically integrable, high‐sensitivity, and high‐reliability magnetic sensors are not yet realized at high temperatures (500 °C). In this study, an integrated on‐chip single‐crystal diamond (SCD) micro‐electromechanical system (MEMS) magnetic transducer is demonstrated by coupling SCD with a large magnetostrictive FeGa film. The FeGa film is multifunctionalized to actuate the resonator, self‐sense the external magnetic field, and electrically readout the resonance signal. The on‐chip SCD MEMS transducer shows a high sensitivity of 3.2 Hz mT⁻¹ from room temperature to 500 °C and a low noise level of 9.45 nT Hz^−1/2 up to 300 °C. The minimum fluctuation of the resonance frequency is 1.9 × 10⁻⁶ at room temperature and 2.3 × 10⁻⁶ at 300 °C. An SCD MEMS resonator array with parallel electric readout is subsequently achieved, thus providing a basis for the development of magnetic image sensors. The present study facilitates the development of highly integrated on‐chip MEMS resonator transducers with high performance and high thermal stability.