We demonstrated the use of exchange-biased giant magnetoresistance (GMR) sensors in Wheatstone bridge for the detection of 10-nm superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs were synthesized via coprecipitation method, exhibiting a superparamagnetic behavior with saturation magnetization of 57 emu/g. The output voltage signal of the Wheatstone bridge exhibits log-linear function of the concentration of SPIONs (from 10 ng/ml to 0.1 mg/ml), making the sensors suitable for use as a SPION concentration detector. Thus the combination of 10 nm SPIONs and the exchange-biased GMR sensors has potential to be used in the bio-detection applications where ultra-small bio-labels are needed.
- Giant magnetoresistance (GMR)
- magnetic sensor
- superparamagnetic nanoparticles
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering