Detection of 10-nm superparamagnetic iron oxide nanoparticles using exchange-biased GMR sensors in wheatstone bridge

L. Li, K. Y. Mak, Chi Wah Leung, S. M. Ng, Z. Q. Lei, P. W.T. Pong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

22 Citations (Scopus)


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.
Original languageEnglish
Article number6559174
Pages (from-to)4056-4059
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number7
Publication statusPublished - 2 Aug 2013


  • Giant magnetoresistance (GMR)
  • magnetic sensor
  • superparamagnetic nanoparticles

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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