Detection of iron-oxide magnetic nanoparticles using magnetic tunnel junction sensors with conetic alloy

Z. Q. Lei; Chi Wah Leung; L. Li; G. J. Li; G. Feng; A. Castillo; P. J. Chen; P. T. Lai; P. W.T. Pong

doi:10.1109/TMAG.2011.2157099

Detection of iron-oxide magnetic nanoparticles using magnetic tunnel junction sensors with conetic alloy

Z. Q. Lei, Chi Wah Leung, L. Li, G. J. Li, G. Feng, A. Castillo, P. J. Chen, P. T. Lai, P. W.T. Pong

Research output: Journal article publication › Journal article › Academic research › peer-review

5 Citations (Scopus)

Abstract

We demonstrated the detection of 20-nm iron-oxide magnetic nanoparticles (MNPs) using Al2O3magnetic tunnel junction sensors (MTJs) with Conetic alloy. Conetic alloy Ni77Fe14Cu5Mo4was deposited as the MTJ free layer and pinned layer due to its magnetically soft properties. The magnetoresistance (MR) curves of MTJs with Conetic alloy showed tunneling magnetoresistance of 8.0% with small hysteresis and high linearity in the sensing region, after applying an external magnetic field of 14 Oe along the hard axis. The sensitivity of the MTJ sensors with Conetic alloy was determined to be 0.3%/Oe within a linear region at room temperature. The MNPs of three different concentrations were successfully detected by the shifts of the MR loops of the MTJs, and it was observed that the resistance deviations of the MTJ sensors increased with the logarithm of MNP concentrations. The maximum resistance deviation was 0.16 Ω for an MNP concentration of 20.0 mg/mL. MTJ sensors, together with MNPs, are a promising platform for future biosensor applications, and this paper shows that Conetic alloy is feasible for improving the performance of this platform.

Original language	English
Article number	6027820
Pages (from-to)	2577-2580
Number of pages	4
Journal	IEEE Transactions on Magnetics
Volume	47
Issue number	10
DOIs	https://doi.org/10.1109/TMAG.2011.2157099
Publication status	Published - 1 Oct 2011

Keywords

Iron-oxide magnetic nanoparticles
magnetic sensors
magnetic tunnel junction (MTJ)

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

More information

10.1109/TMAG.2011.2157099

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title = "Detection of iron-oxide magnetic nanoparticles using magnetic tunnel junction sensors with conetic alloy",

abstract = "We demonstrated the detection of 20-nm iron-oxide magnetic nanoparticles (MNPs) using Al2O3magnetic tunnel junction sensors (MTJs) with Conetic alloy. Conetic alloy Ni77Fe14Cu5Mo4was deposited as the MTJ free layer and pinned layer due to its magnetically soft properties. The magnetoresistance (MR) curves of MTJs with Conetic alloy showed tunneling magnetoresistance of 8.0% with small hysteresis and high linearity in the sensing region, after applying an external magnetic field of 14 Oe along the hard axis. The sensitivity of the MTJ sensors with Conetic alloy was determined to be 0.3%/Oe within a linear region at room temperature. The MNPs of three different concentrations were successfully detected by the shifts of the MR loops of the MTJs, and it was observed that the resistance deviations of the MTJ sensors increased with the logarithm of MNP concentrations. The maximum resistance deviation was 0.16 Ω for an MNP concentration of 20.0 mg/mL. MTJ sensors, together with MNPs, are a promising platform for future biosensor applications, and this paper shows that Conetic alloy is feasible for improving the performance of this platform.",

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author = "Lei, {Z. Q.} and Leung, {Chi Wah} and L. Li and Li, {G. J.} and G. Feng and A. Castillo and Chen, {P. J.} and Lai, {P. T.} and Pong, {P. W.T.}",

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AU - Feng, G.

AU - Castillo, A.

AU - Chen, P. J.

AU - Lai, P. T.

AU - Pong, P. W.T.

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N2 - We demonstrated the detection of 20-nm iron-oxide magnetic nanoparticles (MNPs) using Al2O3magnetic tunnel junction sensors (MTJs) with Conetic alloy. Conetic alloy Ni77Fe14Cu5Mo4was deposited as the MTJ free layer and pinned layer due to its magnetically soft properties. The magnetoresistance (MR) curves of MTJs with Conetic alloy showed tunneling magnetoresistance of 8.0% with small hysteresis and high linearity in the sensing region, after applying an external magnetic field of 14 Oe along the hard axis. The sensitivity of the MTJ sensors with Conetic alloy was determined to be 0.3%/Oe within a linear region at room temperature. The MNPs of three different concentrations were successfully detected by the shifts of the MR loops of the MTJs, and it was observed that the resistance deviations of the MTJ sensors increased with the logarithm of MNP concentrations. The maximum resistance deviation was 0.16 Ω for an MNP concentration of 20.0 mg/mL. MTJ sensors, together with MNPs, are a promising platform for future biosensor applications, and this paper shows that Conetic alloy is feasible for improving the performance of this platform.

AB - We demonstrated the detection of 20-nm iron-oxide magnetic nanoparticles (MNPs) using Al2O3magnetic tunnel junction sensors (MTJs) with Conetic alloy. Conetic alloy Ni77Fe14Cu5Mo4was deposited as the MTJ free layer and pinned layer due to its magnetically soft properties. The magnetoresistance (MR) curves of MTJs with Conetic alloy showed tunneling magnetoresistance of 8.0% with small hysteresis and high linearity in the sensing region, after applying an external magnetic field of 14 Oe along the hard axis. The sensitivity of the MTJ sensors with Conetic alloy was determined to be 0.3%/Oe within a linear region at room temperature. The MNPs of three different concentrations were successfully detected by the shifts of the MR loops of the MTJs, and it was observed that the resistance deviations of the MTJ sensors increased with the logarithm of MNP concentrations. The maximum resistance deviation was 0.16 Ω for an MNP concentration of 20.0 mg/mL. MTJ sensors, together with MNPs, are a promising platform for future biosensor applications, and this paper shows that Conetic alloy is feasible for improving the performance of this platform.

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Detection of iron-oxide magnetic nanoparticles using magnetic tunnel junction sensors with conetic alloy

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