Browsing by Author "Mandal, Sanjay"

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    Enhancing the sensitivity of magnetoelectric sensors by increasing the operating frequency
    Petrie, Jonathan; Viehland, Dwight D.; Gray, David; Mandal, Sanjay; Sreenivasulu, Gollapudi; Srinivasan, Gopalan; Edelstein, Alan S. (American Institute of Physics, 2011-12-15)
    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/root Hz at 1Hz in a magnetically unshielded environment. (C) 2011 American Institute of Physics. [doi:10.1063/1.3668752]
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    Shifting the operating frequency of magnetoelectric sensors
    Petrie, Jonathan; Gray, David; Viehland, Dwight D.; Sreenivasulu, Gollapudi; Srinivasan, Gopalan; Mandal, Sanjay; Edelstein, Alan S. (American Institute of Physics, 2012-04-01)
    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/root Hz at 1 Hz in a magnetically unshielded environment. (C) 2012 American Institute of Physics. [doi:10.1063/1.3677840]