Progress toward a thousandfold reduction in 1∕f noise in magnetic sensors using an ac microelectromechanical system flux concentrator (invited)

Edelstein, A. S.; Fischer, Greg; Pedersen, Michael; Nowak, E. R.; Cheng, Zhangyu; Nordman, C.

doi:10.1063/1.2170067

Cited by 99 publications

(65 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Attempts to improve field detectivity at low frequencies include low temperature annealing [14,15] and using flux concentrators to amplify the magnetic field at the sensor [5,6,16,17]. An interesting suggestion is to use an ac microelectromechanical flux concentrator system to mitigate the nuisance of 1/f noise by modulating the sensor magnetic field to a higher frequency regime where the 1/f noise is lower [18].…”

Section: Introductionmentioning

confidence: 99%

Low-frequency noise in planar Hall effect bridge sensors

Persson¹,

Bejhed²,

Nguyen³

et al. 2011

Sensors and Actuators A: Physical

View full text Add to dashboard Cite

The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a knee frequency of around 400 Hz. The 1/f-like excess noise can be described by the phenomenological Hooge equation with a Hooge parameter of γ H =0.016. The detectivity is shown to depend on the total length, width and thickness of the bridge branches. Increasing the total length by a factor of 10 improves the detectivity by a factor of 10 1/2 . Moreover, the detectivity is shown to depend on the amplitude of the applied magnetic field, revealing a magnetic origin to part of the 1/f noise.

show abstract

Section: Introductionmentioning

confidence: 99%

Low-frequency noise in planar Hall effect bridge sensors

Persson¹,

Bejhed²,

Nguyen³

et al. 2011

Sensors and Actuators A: Physical

View full text Add to dashboard Cite

show abstract

“…2,3 In small sensors, such as magnetoresistive sensors, this is done by using movable flux concentrators on microelectromechanical systems (MEMS) structures to modulate the magnetic field at the position of the sensor. The field modulation increases the operating frequency of the sensor to tens of kHz.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the sensitivity of magnetoelectric sensors by increasing the operating frequency

Petrie

Viehland

Gray

et al. 2011

Journal of Applied Physics

View full text Add to dashboard Cite

Articles you may be interested inEnhanced sensitivity in magnetoelectric current-sensing devices with frequency up-conversion mechanism by modulating the magnetostrictive strain J. Appl. Phys. 115, 17E505 (2014) We present a field modulation technique that increases the operating frequency of magnetoelectric (ME) sensors so that it can match the mechanical resonance frequency of the sensor. This not only improves the sensitivity but also reduces the effect of 1/f noise that is inherent at low frequencies. The technique, which is shown to apply to both symmetric and asymmetric ME sensors, relies on the strong, nonlinear magnetic field dependence of the magnetostriction. The combination of a lower 1/f noise and enhanced response at resonance has increased the signal to noise ratio of a symmetric sensor by two orders of magnitude. The detection limit of this sensor was lowered from 90 to 7 pT/ ffiffiffiffiffi ffi Hz p at 1 Hz in a magnetically unshielded environment.

show abstract

“…4,5 Because of the need for moving a larger mass flux concentrator it is very difficult to use these to modulate the magnetic field of centimeter sized sensors. Modulation frequencies of 100 Hz were achieved using flux concentrators on a rotating disk, but unfortunately acoustic vibrations increased the background noise.…”

mentioning

confidence: 99%

Shifting the operating frequency of magnetoelectric sensors

Petrie

Gray

Viehland

et al. 2012

Journal of Applied Physics

View full text Add to dashboard Cite

A method is presented for increasing the operating frequency of symmetric and asymmetric magnetoelectric (ME) sensors so that the operating frequency can be equal to the mechanical resonance frequency of the sensor. This increase improves the signal to noise ratio of a symmetric sensor by at least two orders of magnitude because it mitigates the effect of 1/f noise and the sensor has an increased response at its resonant frequency. The method is based on the strong, nonlinear magnetic field dependence of the magnetostriction. Our method has lowered the detection limit to 4 pT/Hz at 1 Hz in a magnetically unshielded environment.

show abstract

Progress toward a thousandfold reduction in 1∕f noise in magnetic sensors using an ac microelectromechanical system flux concentrator (invited)

Cited by 99 publications

References 18 publications

Low-frequency noise in planar Hall effect bridge sensors

Low-frequency noise in planar Hall effect bridge sensors

Enhancing the sensitivity of magnetoelectric sensors by increasing the operating frequency

Shifting the operating frequency of magnetoelectric sensors

Contact Info

Product

Resources

About