Fabrication of micromechanically-modulated MgO magnetic tunnel junction sensors

We have developed a hybrid magnetoresistive (MR)-MEMS sensor based on the monolithic integration of magnetic thin films and SOI MEMS fabrication techniques. MgO magnetic tunnel junctions (MTJ) on bulk micromachined silicon structures form a hybrid sensing platform in which the MEMS structure is used to mechanically modulate the magnetic field signal detected by the MTJ. We demonstrate the modulation of DC magnetic field through the mechanical motion of the cantilever at resonance. This allows for the improved detection of small DC or low frequency magnetic signals modulated into the high frequency region where the 1/f noise is lower.