Sensitive Magnetometer Incorporating a High-Q Nonlinear Mechanical Resonator with No Magnetic Element

This paper proposes a novel scheme for measuring magnetic field strength that can be optimized to detect very small changes about a given local level. The device consists simply of an oscillator employing a high-Q nonlinear mechanical resonator carrying an electrically conductive element. Oscillation of the conductor in the magnetic field generates an electric potential that drives a current around a closed resistive loop to damp the motion of the resonator. Variations in magnetic field therefore alter the resonator's amplitude and so also the measured frequency of the overdriven resonator. An example device is capable of detecting perturbations in earth's magnetic field smaller than 1 part in 10 6 . The proposed magnetometer may be the first practical application for a nonlinear mechanical resonator.