Biomagnetic measurement using by thin film magnetic field sensor array

利用SrTiO薄膜、非晶CoNbZr薄膜和Cu/Cr薄膜制作的共面线，研制了一种高灵敏度的薄膜传感器。这种薄膜提高了磁场传感器的灵敏度，同时实现了超过100度/Oe的相位变化和超过-40 dB的增益。由于SrTiO薄膜的高介电常数，使传感器的灵敏度比SiO2薄膜提高了1.6倍。当施加弱磁场时，使用双混频器时间差（DMTD）方法检测到小的相位变化。将该传感器应用于无磁屏蔽的心磁图（MCG）测量。在没有磁屏蔽的情况下成功地测量了16个点处的MCG信号，并且发现这些信号与用SQUID获得的MCG信号大致一致。

A very sensitive thin film sensor was developed using a coplanar line fabricated from SrTiO film, amorphous CoNbZr film and Cu/Cr film. This film enhanced the sensitivity of the magnetic field sensor, a phase change of more than 100 degrees/Oe and gain of over -40 dB being achieved simultaneously. The sensor with SrTiO film enhanced the sensitivity about 1.6 times greater than that with SiO2 film because of the high permittivity of the SrTiO film. A small phase change was detected using a Dual Mixer Time Difference (DMTD) method when a weak magnetic field was applied. The sensor was applied to magnetocardiogram (MCG) measurement without magnetic shielding. Measurement of the MCG signals at 16 points without magnetic shielding were successful, and these signals were found to roughly agree with MCG signals obtained with a SQUID.