A highly sensitive and wide-range resonant magnetic micro-sensor based on a buckled micro-beam

Abstract

We experimentally demonstrate a miniature highly sensitive wide-range resonant magnetic Lorentz-force micro-sensor. The concept is demonstrated based on the detection of the resonance frequency of an in-plane electrothermally heated straight resonator operated near the buckling point. The frequency shift is measured with optical sensing (laser) and the device is operated at atmospheric pressure. The frequency shift of the micro-sensor becomes very sensitive to any external disturbances around the buckling zone as indicated by the analytical model and experimental data, which show high sensitivity. The magnetometer demonstrates a measured sensitivity (S) of 33.9/T, which is very high compared to the state of the art. In addition, the micro-sensor shows a bi-linear behaviour with good linearity in two magnetic field regimes, low and high, with low power consumption around 0.2 mW. These attractive features make the proposed micro-sensor promising for various low-cost magnetic applications.