Magnetic Tunnel Junction based Gradiometer for Detection of Cracks in Cement
KAUST DepartmentMaterial Science and Engineering Program
Physical Science and Engineering (PSE) Division
Online Publication Date2021-07-08
Print Publication Date2021-11
Embargo End Date2023-07-01
Permanent link to this recordhttp://hdl.handle.net/10754/670103
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AbstractMagnetic flux leakage (MFL) testing is a widely used technology for detecting structural defects in industry, where new magnetic sensors can provide an enhanced detectability. We have fabricated and developed vortex magnetic tunnel junctions (MTJs) into a new MFL probe, by designing a well-balanced magnetic gradiometer with a base length of 4 cm. Such gradiometer has exhibited a field detectability of 1.6 𝑛𝑇/√𝐻𝑧 at 1 kHz, and a superior common-mode rejection ratio (CMRR) of 82 dB. We have studied multiple configurations of crack detection in weakly magnetic cement by simulations, and provided corresponding experimental confirmations by this MFL probe. It has achieved a large standoff distance of 22 mm, which finds its applications in energy industry and other infrastructural systems.
CitationHe, G., Zhang, Y., Hu, Y., Zhang, X., & Xiao, G. (2021). Magnetic Tunnel Junction based Gradiometer for Detection of Cracks in Cement. Sensors and Actuators A: Physical, 112966. doi:10.1016/j.sna.2021.112966
SponsorsThis work was supported by King Abdullah University of Science and Technology (KAUST) through the Sensor Initiative. We thank colleagues at KAUST for discussion and collaboration. Y.Z. acknowledges support from Fermilab-Graduate Instrumentation Research Award from DOE grant number DE-AC05-00OR22725. We used the Heidelberg MLA150 Maskless Aligner, which was under the support of a National Science Foundation Grant No. DMR-1827453.