Optimization of an MEMS Magnetic Thin Film Vibrating Magnetometer

This paper presents models developed through analytical or numerical computation and finite-element analysis to improve the resolution of a new kind of vibrating magnetometers. This peculiar magnetometer uses the piezoelectric transduction to actuate a quartz resonator at its resonance frequency taking advantage of the high Q factor of a quartz resonator to achieve high resolution. The magnetic sensitive element is a thin ferromagnetic film of nickel-cobalt, which is sputtered on the moving beams of the resonator. This magnetic thin film applies a periodic torque on the resonator, shifting its resonance frequency. This torque depends on the magnetic field applied; therefore, the value of the magnetic field can be deduced from the frequency shift measurement. The aim of this paper is to develop and improve sensitivity models, which will be useful tools in the future work to establish the optimal geometry for a resonator and the best position of the magnetic thin film on it in order to improve the sensitivity and resolution of the global sensor.