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|Author(s):||Wendy R. Altman; John M. Moreland; Stephen E. Russek; Victor M. Bright;|
|Title:||Optimization of spin-valve parameters for magnetic bead trapping and manipulation|
|Published:||February 06, 2010|
|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|
|Pages:||pp. 3236 - 3239|
|Keywords:||spin-valve,magnetic beads,microfluidic,magnetic manipulation,switchable magnetic trap|
|Research Areas:||Condensed Matter Physics|