National Physical Laboratory

Ultra small Hall sensors

Double-cross InSb Hall sensor with the lead width of 600 nm. An FePt bead (150 nm diameter) is place on top of the Hall sensor (not to scale). Inset: HR TEM image of a bead.
Double-cross InSb Hall sensor with the lead width of 600 nm. An FePt bead (150 nm diameter) is placed on top of the Hall sensor (not to scale). Inset: HR TEM image of a bead.


Detection of the bead based on the ac-dc phase-control measurement technique. Blue line shows the real signal due to the presence of the paramagnetic bead.
Detection of the bead based on the ac-dc phase-control measurement technique. Blue line shows the real signal due to the presence of the paramagnetic bead.

Our ultra-sensitive InSb Hall devices (size ~ 0.3 – 5 µm) can be used for the detection of magnetic nanobeads.

To eliminate spurious signals from inductive couplings and foreign ferromagnetic materials, which are more significant for smaller devices, we developed a phase-sensitive AC-DC Hall magnetometry for clear and reliable separation of real and parasitic magnetic signals of a very small magnitude.

Using this technique we successfully demonstrated detection of individual magnetic beads with diameter of 120 nm – 1 µm and a magnetic moment down to 107 μB. [1,2]

Superior performance of the Hall devices studied here opens up new horizons for the detection of even smaller magnetic moments, which is of high importance both for metrological applications and highly sensitive biological and environmental detectors.

References

  1. Modelling and optimization of submicron Hall sensors for the detection of superparamagnetic beads
    A. Manzin, V. Nabaei and O. Kazakova,
    J. Appl. Phys. 111, 07E513 (2012).
  2. Detection and susceptibility measurements of a single Dynal bead
    L. Di Michele, C. Shelly, P. de Marco, P. See, D. Cox, and O. Kazakova
    J. Appl. Phys., 110, 063916 (2011)
  3. Single particle detection: Phase control in submicron Hall sensors
    L. Di Michele, C. Shelly, J. Gallop and O. Kazakova
    Journal of Applied Physics, 108, 103918 (2010)
  4. Ultrasmall particle detection using a submicron Hall sensor
    O. Kazakova, V. Panchal, J. Gallop, P. See, D. C. Cox, M. Spasova and L. F. Cohen
    Journal of Applied Physics, 107, 09E708 (2010)
  5. Detection of a Micron-Sized Magnetic Particle Using InSb Hall Sensor
    O. Kazakova, J. C. Gallop, P. See, D. Cox, G. K. Perkins, J. D. Moore and L. F. Cohen
    Ieee Transactions On Magnetics, 45, 4499-4502 (2009)
  6. Optimization of 2DEG InAs/GaSb Hall Sensors for Single Particle Detection
    O. Kazakova, J. C. Gallop, D. C. Cox, E. Brown, A. Cuenat and K. Suzuki
    Ieee Transactions On Magnetics, 44, 4480-4483 (2008)
Last Updated: 26 Apr 2012
Created: 26 Jul 2011