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Single particle detection: phase control in submicron Hall sensors.

Di Michele, L*; Shelly, C*; Gallop, J C; Kazakova, O (2010) Single particle detection: phase control in submicron Hall sensors. J. Appl. Phys., 108 (10). 103918

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We present a phase-sensitive AC-DC Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm - 5 um. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of m=10^8 uB has been achieved with a 600 nm-wide sensor.

Item Type: Article
Keywords: Hall sensor, superparamegnetic nanoparticle, single particle detection, nanosensor
Subjects: Quantum Phenomena
Quantum Phenomena > Nanophysics
Identification number/DOI: 10.1063/1.3514097
Last Modified: 02 Feb 2018 13:15
URI: http://eprintspublications.npl.co.uk/id/eprint/4868

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