On-Chip Diamond MEMS Resonators Magnetic Sensing up to 500°C

Stable-operation in the high-temperature regimes (300°C~500°C) for the current magnetic sensors has the thermal-reliability problem. In this work, we propose and demonstrate an on-chip single-crystal diamond (SCD) MEMS magnetic sensor able to work at 500°C by integrating a magnetostrictive FeGa film on a SCD cantilever. The SCD MEMS magnetic sensor exhibits a high thermal-stability operation up to 500°C, showing a magnetic sensitivity of 2.8 Hz/mT at 25°C, 7.5 Hz/mT at 300°C, and 17.7 Hz/mT at 500°C, respectively. The concept of a SCD resonator functionalized with a magnetostrictive film offers a promising strategy to develop high-temperature magnetic sensors with high thermal-reliability.