Electrically insulating cantilever magnetometer with mutually isolated and integrated thermometry, background elimination and null detection

摘要

A high sensitivity torque and force cantilever magnetometer having a cantilever with isolated capacitance detection and nulling circuits which provides increased sensitivity and accuracy to measurements of a magnetic moment of a sample placed on the cantilever and exposed to a magnetic field. Magnetic detection is by electrical capacitance between a metallized plate and the cantilever. Alternatively, magnetic detection is by electrical resistance of a piezoactive circuit deposited on the surface of the cantilever. The cantilever can be used to measure both isotropic and anisotropic magnetism and is capable of simultaneously measuring the electrical conductivity of the sample using an integrated electrically isolated circuit. The cantilever is constructed of multiple layers of conducting and insulating materials to eliminate leakage current. The magnetometer measures the magnitude of a current through a null detection circuit having at least one nulling loop deposited on the cantilever required to maintain a constant capacitance between the cantilever and a metallized plate to determine the magnetization of the sample. The null detection circuit eliminates capacitance drift and improves the accuracy of the magnetometer.