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Highly-sensitive magnetic sensor for detecting magnetic nanoparticles based on magnetic tunnel junctions at a low static field

Authors :
Yasuo Ando
Young Keun Kim
Muftah Al-Mahdawi
Zhenhu Jin
Myeong Soo Kim
Mikihiko Oogane
Thomas Myeongseok Koo
Source :
AIP Advances, Vol 11, Iss 1, Pp 015046-015046-5 (2021)
Publication Year :
2021
Publisher :
AIP Publishing LLC, 2021.

Abstract

Magnetic sensors to detect magnetic nanoparticles (MNPs) towards biomedical applications require very high sensitivity at low magnetic fields. Here we report a magnetic sensor consisting of a magnetic tunnel junction (MTJ) with a synthetic antiferromagnetic free layer. This sensor exhibits a low magnetic anisotropy and sensitivities of over 18%/Oe at low fields in the range of 0 to 3 Oe. We employ superparamagnetic MNPs with a large diameter of 200 nm. The sensor’s transfer curves show the magnetoresistance (MR) variations as a function of MNP concentration. We demonstrate the detection capability of MNP amounts of below 500 ng and low MNP concentrations of 0.01, 0.1, and 1 mg/ml in solvents. This result suggests that the combination of high-sensitivity TMR sensors and large MNPs has a substantial potential for biomarker detection applications.

Details

Language :
English
ISSN :
21583226
Volume :
11
Issue :
1
Database :
OpenAIRE
Journal :
AIP Advances
Accession number :
edsair.doi.dedup.....498c648c720ffad5654555ca8783185a