Operational amplifier circuits for magnetic sensing using perpendicular low-coercivity nanoscale spin transfer torque magnetic tunnel junctions
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Author (Corporation)
Publication date
15.03.2025
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Type
01A - Journal article
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Parent work
IEEE Sensors Journal
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Volume
25
Issue / Number
6
Pages / Duration
9550-9559
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IEEE
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Abstract
This article presents the use of nanoscale perpendicular spin transfer torque magnetic tunnel junctions (STT-MTJs) as magnetic sensing units in which the conditioning electronics consists of simple circuits based on operational amplifier (OpAmp). This approach allows low-power ( μ W), nanoscale (50–100 nm), and high-frequency (100–1000 kHz) magnetic measurements, with, in addition, presenting CMOS compatibility for future mass production. Noise levels as low as 2 μ T/ √ Hz are achieved over a dynamic range of up to tens of milliteslas. The different circuits are demonstrated through theoretical modeling and confirmed with experimental measurements on fabricated devices, validating the working principle with sensing elements among the smallest ever reported to our knowledge. Further improvements are, however, required, in both the proposed electronics and stacks of the junctions, to lower the noise and reach the sub-microtesla noise level. Hence, this technology could open the way to new metrological possibilities, unaddressed with existing technologies, including photolithographic mask alignment or high-frequency current measurements, in the case of industrial applications, as well as measurements of magnetic beads and ferromagnetic particle detection in life sciences.
Keywords
Sensors, Magnetic tunneling, Magnetic sensors, Magnetic field measurement, Circuits, Voltage measurement, Junctions, Probes, Noise, Nanoscale devices
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ISBN
ISSN
1530-437X
1558-1748
1558-1748
Language
English
Created during FHNW affiliation
Yes
Strategic action fields FHNW
Publication status
Published
Review
Peer review of the complete publication
Open access category
Closed
License
Citation
Nicolas, H., Sousa, R. C., Mora-Hernández, A., Prejbeanu, I.-L., Hebrard, L., Kammerer, J.-B., & Pascal, J. (2025). Operational amplifier circuits for magnetic sensing using perpendicular low-coercivity nanoscale spin transfer torque magnetic tunnel junctions. IEEE Sensors Journal, 25(6), 9550–9559. https://doi.org/10.1109/jsen.2025.3537700