TY - JOUR
T1 - A thin film magnetic field sensor of sub-pT resolution and magnetocardiogram (MCG) measurement at room temperature
AU - Yabukami, S.
AU - Kato, K.
AU - Ohtomo, Y.
AU - Ozawa, T.
AU - Arai, K. I.
N1 - Funding Information:
We wish to thank Dr. N. Nakasato of Kohnan Hospital, Mr. S. Sato of NEC Tokin, and Prof. K. Kobayashi of Iwate University for their useful advice about MCG measurement. We are also grateful to Prof. H. Matsuki and Prof. F. Sato of Tohoku University for help with MCG measurement in a magnetic shielded room, and Prof. M. Kimura and Prof. Y. Kamo of Tohoku-Gakuin University for assisting in the fabrication of the thin film sensor. This study was partly supported by a grant for Development of System and Technology for Advanced Measurement and Analysis (Japan Science and Technology Agency). It was also partly supported by a Grant-in-Aid for Scientific Research (Japan Society for the Promotion of Science).
PY - 2009/4
Y1 - 2009/4
N2 - We developed a very sensitive high-frequency carrier-type thin film sensor with a sub-pT resolution using a transmission line. The sensor element consists of Cu conductor with a meander pattern (20 mm in length, 0.8 mm in width, and 18 μm in thickness), a ground plane, and amorphous CoNbZr film (4 μm in thickness). The amplitude modulation technique was employed to enhance the magnetic field resolution for measurement of the high-frequency field (499 kHz), a resolution of 7.10×10-13 T/Hz1/2 being achieved, when we applied an AC magnetic field at 499 kHz. The phase detection technique was applied for measurement of the low frequency field (around 1 Hz). A small phase change was detected using a dual mixer time difference method. A high phase change of 130°/Oe was observed. A magnetic field resolution of 1.35×10-12 T/Hz1/2 was obtained when a small AC field at 1 Hz was applied. We applied the sensor for magnetocardiogram (MCG) measurement using the phase detection technique. We succeeded in measuring the MCG signal including typical QRS and T waves, and compared the MCG with a simultaneously obtained conventional electrocardiogram (ECG) signal.
AB - We developed a very sensitive high-frequency carrier-type thin film sensor with a sub-pT resolution using a transmission line. The sensor element consists of Cu conductor with a meander pattern (20 mm in length, 0.8 mm in width, and 18 μm in thickness), a ground plane, and amorphous CoNbZr film (4 μm in thickness). The amplitude modulation technique was employed to enhance the magnetic field resolution for measurement of the high-frequency field (499 kHz), a resolution of 7.10×10-13 T/Hz1/2 being achieved, when we applied an AC magnetic field at 499 kHz. The phase detection technique was applied for measurement of the low frequency field (around 1 Hz). A small phase change was detected using a dual mixer time difference method. A high phase change of 130°/Oe was observed. A magnetic field resolution of 1.35×10-12 T/Hz1/2 was obtained when a small AC field at 1 Hz was applied. We applied the sensor for magnetocardiogram (MCG) measurement using the phase detection technique. We succeeded in measuring the MCG signal including typical QRS and T waves, and compared the MCG with a simultaneously obtained conventional electrocardiogram (ECG) signal.
KW - Magnetic field sensor
KW - Magnetocardiogram
KW - Thin film sensor
UR - http://www.scopus.com/inward/record.url?scp=60949100676&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=60949100676&partnerID=8YFLogxK
U2 - 10.1016/j.jmmm.2008.11.083
DO - 10.1016/j.jmmm.2008.11.083
M3 - Article
AN - SCOPUS:60949100676
VL - 321
SP - 675
EP - 678
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
SN - 0304-8853
IS - 7
ER -