A novel inverse-magnetostrictive type pressure sensor with planar sensing inductor

In this study, a novel planar inductor to detect the pressure sensor is proposed. The planar inductor consists of planar coil and CoFeB films. The proposed sensor exploits the inverse-magnetostriction effect to change the permeability of the CoFeB film by pressure load. This permeability variation will further result in the inductance difference of the planar inductor. Consequently the relationship between the pressure and inductance can be obtained by the inductance measurement. To demonstrate the presented concept, prototype inverse-magnetostrictive type pressure sensors with planar sensing inductor (Al planar coil and CoFeB films) have been implemented and tested. Sensitivity measurements show the gauge factor of the novel pressure sensor is approximate 280. To support the proposed concept, the vibrating sample magnetometer (VSM) measurements show the magnetic anisotropy of the CoFeB film (extracted from the hysteresis loops) is changed due to the applied pressure load.