Microelectromechanical (MEMS)-based magnetostrictive magnetometer

US5998995A · kind A · utility

Assignee

• THE JOHNS HOPKINS UNIVERSITY · US

Inventors

• Robert Osiander · Ellicott City, US
• Scott Ecelberger · Laurel, US
• Robert B. Givens · Frederick, US
• Dennis K. Wickenden · Woodbine, US
• John C. Murphy · Clarksville, US
• Thomas J. Kistenmacher · Columbia, US

Key dates

• Filing date: Oct 3, 1997
• Grant date: Dec 7, 1999
• Expiry date: Oct 3, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/02
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A microelectromechanical-based magnetostrictive magnetometer that uses, as an active element, a commercial (001) silicon microcantilever coated with an amorphous thin film of the giant magnetostrictive alloy Terfenol-D and a compact optical beam deflection transduction scheme. A set of Helmholtz coils is used to create an ac magnetic excitation field for driving the mechanical resonance of the coated microcantilever. When the coated microcantilever is placed in a dc magnetic field, the dc field will change the amplitude at the mechanical resonance of the coated microcantilever thereby causing a deflection that can be measured. The magnetometer has been demonstrated with a sensitivity near 1 .mu.T.