Altman, W.
, Moreland, J.
, Russek, S.
and Bright, V.
(2010),
Optimization of spin-valve parameters for magnetic bead trapping and manipulation, Journal of Magnetism and Magnetic Materials
(Accessed May 9, 2025)
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Optimization of spin-valve parameters for magnetic bead trapping and manipulation
Published
Author(s)
, , , Victor M. Bright
Abstract
Magneto-optic Kerr effect (MOKE) and magnetoresistance (MR) measurements were used to measure the switching characteristics of spin-valve (SV) arrays currently being developed to trap and release superparamagnetic beads within a fluid medium. The effect of SV size on switching observed by MOKE showed that a 1 υm x 8 υm SV element was found to have optimal switching characteristics. MR measurements on a single 1 υm x 8 υm SV switched with either an external applied magnetic field or a local magnetic field generated by an integrated write wire (current density ranging from 106 to 107 A/cm2) confirmed the MOKE findings. The 1 υm x 8 υm SV low field switching was observed to be +8 and -2 mT with two stable states at zero field; the high field switching was observed to be -18 mT. The low switching fields and the large magnetic moment of the SV trap along with our observation of minimal magnetostatic effect for dense arrays are necessary design characteristics for high-force, "switchable-magnet," microfluidic bead trap applications.Citation
Journal of Magnetism and Magnetic Materials
Volume
322
Pub Type
Journals
Keywords
spin-valve, magnetic beads, microfluidic, magnetic manipulation, switchable magnetic trap
Citation
Issues
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Created February 5, 2010, Updated October 12, 2021