Electricity: measuring and testing – Magnetic – Magnetometers
Patent
1996-04-30
1998-04-14
Snow, Walter E.
Electricity: measuring and testing
Magnetic
Magnetometers
324244, 324260, 324661, G01R 3302, G01R 2728
Patent
active
057396868
ABSTRACT:
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 nulling loops deposited on the cantilever required to maintain a constant capacitance between the cantilever and a metallized plate to determine the magnetization of the sample. A magnetometer having two cantilevers where one cantilever is used as a reference to eliminate background noise and temperature and magnetic field variations from measurements taken of a sample on the second cantilever is also provided. The null detection circuit eliminates capacitance drift and improves the accuracy of the magnetometer.
REFERENCES:
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C. Voigt et al., "A Simple Compensating Torquemeter for Use in High Field Solenoids"; Oct. 1971.
M. Chaparala et al., "Capacitance Platform Magnetometer for Thin Film and Small Crystal Superconductor Studies", AIP Conference Proceedings 273: Superconductivity And its Applications, Buffalo, NY, pp. 407-413; 1992.
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Chaparala Murali
Naughton Michael J.
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