MEMS magnetometer based on magnetorheological elastomer

To develop a simple and low-cost MEMS magnetometer, a novel sensor based on the magnetostrictive effect of magnetorheological elastomer is proposed. The micromechanical sensor consists of a silicon sensitivity diaphragm embedded with a piezoresistive Wheatstone bridge, and a magnetorheological elastomer layer attached on the sensitivity diaphragm. The interaction between the magnetic field and the elastomer generates a deflection of the sensitivity diaphragm, which changes the piezoresistance and unbalances a Wheatstone bridge. The experimental results show that the sensor has good linearity in the magnetic field range of 0-120 kA/m and the saturation magnetic field is ∼150 kA/m. This simple, low-cost, low-power sensor is easily integrated with electronic circuits using the MEMS processes.