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| Single Magnetic Bead Detection in a Microfluidic Chip Using Planar Hall Effect Sensor |
| Journal of Magnetics, Volume 19, Number 1, 31 Mar 2014, Pages 10-14 |
Hyuntai Kim (Department of Materials Science and Engineering, Chungnam National University), Venu Reddy (Department of Materials Science and Engineering, Chungnam National University), Kun Woo Kim (Department of Materials Science and Engineering, Chungnam National University), Ilgyo Jeong (Department of Materials Science and Engineering, Chungnam National University), Xing Hao Hu (Department of Materials Science and Engineering, Chungnam National University), CheolGi Kim *  (Department of Materials Science and Engineering, Chungnam National University) |
| Abstract |
In this study, we fabricate an integrated microfluidic chip with a planar Hall effect (PHE) sensor for single
magnetic bead detection. The PHE sensor was constructed with a junction size of 10 μm × 10 μm using a
trilayer structure of Ta(3 nm)/NiFe(10 nm)/Cu(1.2 nm)/IrMn(10 nm)/Ta(3 nm). The sensitivity of the PHE
sensor was 19.86 μV/Oe. A diameter of 8.18 μm magnetic beads was used, of which the saturation
magnetization was ~2.1 emu/g. The magnetic susceptibility χ of these magnetic beads was calculated to be ~0.14. The diluted magnetic beads solution was introduced to the microfluidic channel attributing a single bead flow and simultaneously the PHE sensor voltage was measured to be 0.35 μV. The integrated microchip was able to detect a magnetic moment of 1.98 × 10−10 emu.
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| Keywords: planar Hall effect sensor; trilayer structure; single magnetic bead detection; microfluidics |
| DOI: http://dx.doi.org/10.4283/JMAG.2014.19.1.010 |
| Full Text: PDF |
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