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Minimizing 1/f Noise in Magnetic Sensors using an AC MEMS Flux Concentrator

Published online by Cambridge University Press:  26 February 2011

Alan Edelstein ,
Greg A. Fischer ,
Michael Pedersen ,
Edmund Nowak ,
Shu Fan Cheng  and
Cathy A Nordman
Alan Edelstein
Affiliation:
edelstein@arl.army.mil, U.S. Army Research Laboratory, AMSRD-ARL-SE-SS, 2800 Powder Mill Road, Adelphi, Maryland, 20783, United States
Greg A. Fischer
Affiliation:
gfischer@arl.army.mil, U.S. Army Research Laboratory
Michael Pedersen
Affiliation:
pedersen@mems-exchange.org, MEMS Exchange
Edmund Nowak
Affiliation:
nowak@udel.edu, University of Delaware, Physics Department
Shu Fan Cheng
Affiliation:
chengs@anvil.nrl.navy.mil, Naval Research Laboratory
Cathy A Nordman
Affiliation:
cathyn@nve.com, NVE Corp.
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Abstract

We are developing a device, the MEMS flux concentrator, that will greatly decrease the effect of 1/f noise in magnetic sensors. It does this by modulating the incoming signal and thus shifting the operating frequency of the sensor. This is accomplished by placing flux concentrators on MEMS structures that oscillate at kHz frequencies. Depending upon the sensor, shifting the operating frequency reduces the 1/f noise by one to three orders of magnitude at one Hz. We have succeeded in fabricating the necessary MEMS structures and observing the desired kHz normal mode resonant frequency. Only microwatts are required to drive the motion. We have used spin valves for our magnetic sensors. The measured field enhancement provided by the flux concentrators agrees to within 3% with the value estimated from finite element calculations. Noise measurements provide strong evidence that the device is likely to reduce the effect of 1/f noise. Flip chip bonding is likely to allow us to fabricate complete, fully functioning sensors.

Keywords

ferromagneticmagneticmicroelectro-mechanical (MEMS)
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 906: Symposium HH – Magnetic Sensors and Sensing Systems , 2005 , 0906-HH03-09
Copyright
Copyright © Materials Research Society 2006

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