TY - JOUR
T1 - Magnetic sensor based on serial magnetic tunnel junctions for highly sensitive detection of surface cracks
AU - Jin, Zhenhu
AU - Oogane, Mikihiko
AU - Fujiwara, Kosuke
AU - Ando, Yasuo
N1 - Funding Information:
This work was supported by the S-Innovation program, Japan Science and Technology Agency (JST), the Center for Innovative Integrated Electronic System, the Center for Spintronics Research Network (CSRN), and grant-in-aid for scientific research S (Grant No. 24226001).
Publisher Copyright:
© 2017 Author(s).
PY - 2017/11/7
Y1 - 2017/11/7
N2 - Magnetic tunnel junctions (MTJs) that consist of two ferromagnets separated by a thin insulator are among the core devices used in spintronic applications such as magnetic sensors. Since magnetic sensors require high sensitivity for nondestructive eddy current testing, we developed and demonstrated magnetic sensors based on various configurations of serial MTJs. We fabricated sensors with 4, 16, 28, 40, and 52 serial MTJs in various numbers of rows (1, 4, 7, 10, and 13) to detect surface cracks via eddy current testing. All of the sensors could detect and discriminate between surface cracks 0.1 mm in width and 0.1 to 1.0 mm in depth on an aluminum specimen. Systematic studies on the effect of the number of MTJs showed a signal to noise ratio as high as 115 dB when detecting 0.1 mm deep cracks with 28 serial MTJs in 7 rows. This suggests that suitably configured serial MTJ sensors can offer an excellent performance in the detection of tiny surface defects via eddy current testing.
AB - Magnetic tunnel junctions (MTJs) that consist of two ferromagnets separated by a thin insulator are among the core devices used in spintronic applications such as magnetic sensors. Since magnetic sensors require high sensitivity for nondestructive eddy current testing, we developed and demonstrated magnetic sensors based on various configurations of serial MTJs. We fabricated sensors with 4, 16, 28, 40, and 52 serial MTJs in various numbers of rows (1, 4, 7, 10, and 13) to detect surface cracks via eddy current testing. All of the sensors could detect and discriminate between surface cracks 0.1 mm in width and 0.1 to 1.0 mm in depth on an aluminum specimen. Systematic studies on the effect of the number of MTJs showed a signal to noise ratio as high as 115 dB when detecting 0.1 mm deep cracks with 28 serial MTJs in 7 rows. This suggests that suitably configured serial MTJ sensors can offer an excellent performance in the detection of tiny surface defects via eddy current testing.
UR - http://www.scopus.com/inward/record.url?scp=85032948447&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85032948447&partnerID=8YFLogxK
U2 - 10.1063/1.5001098
DO - 10.1063/1.5001098
M3 - Article
AN - SCOPUS:85032948447
VL - 122
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 17
M1 - 174502
ER -