Title :
Flow velocity measurement in microchannels using magnetoresistive chips
Author :
Ferreira, Hugo A. ; Graham, Daniel L. ; Parracho, Pedro ; Soares, Virgínia ; Freitas, Paulo P.
Author_Institution :
INESC, Lisbon, Portugal
fDate :
7/1/2004 12:00:00 AM
Abstract :
On-chip spin valve sensors were used to measure the flow velocity within fabricated poly(dimethylsiloxane) (PDMS) microchannels. Superparamagnetic particles with dimensions of 250 nm in diameter were introduced into a 100 μm wide microchannel, bonded to the chip surface. The flow velocity was determined by measuring the changes in resistance of a pair of spin-valve sensors, 1.65 mm apart from each other, caused by the passage of ensembles of superparamagnetic particles. Flow velocities ranging from 50 to 300 μm/s were estimated, depending on the pressure used to drive the flow. The application of this system provides a means to measure and control flow velocities on microfluidic devices.
Keywords :
microfluidics; paramagnetic materials; spin valves; velocity measurement; 1.65 mm; 250 nm; PDMS microchannels; chip surface; flow velocity measurement; magnetoresistive chips; magnetoresistive devices; microfluidic devices; on-chip spin valve sensors; polydimethylsiloxane; superparamagnetic particles; Bonding; Electrical resistance measurement; Magnetic sensors; Magnetoresistance; Microchannel; Particle measurements; Semiconductor device measurement; Spin valves; Surface resistance; Velocity measurement; Fluidics; magnetoresistive devices; velocity measurement;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2004.830403
