Resonant-type MEMS Magnetic Sensor with FePd Magneto-strictive and PZT Piezo-electric Films

Abstract

This letter describes a resonant-type magnetic sensor with piezo-electric film elements on an Si micro-bridge resonator and other micro-bridge structures with magneto-strictive film to provide structural deformation by external magnetic flux. The sensor was successfully fabricated with thick sol-gel PZT film (1.1 µm) and Fe₆₅Pd₃₅ magneto-strictive film (2 µm) on Si (5 µm) micro-bridges. The resonant behavior was evaluated using the output voltage from the PZT film element on the bridge resonator. The resonant frequency decreased with increasing applied magnetic flux because initial strain of the micro-bridge with the tensile stress of PZT film was relaxed by the magneto-striction.