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High sensitive magnetic field sensing system for measurement of bio-magnetic signal at room temperature

用于室温生物磁信号测量的高灵敏度磁场传感系统

基本信息

批准号：
16206041
负责人：
ARAI Ken ichi
金额：
$ 32.45万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

A highly sensitive magnetic field sensor operating at room temperature shows promise for non-destructive, biomagnetic measurement (such as MCG or MEG). High frequency carrier type sensors have potential for high sensitivity, as in SQUID (Superconducting Quantum Interference Devices). In the present study we developed a very sensitive high-frequency carrier-type magnetic field sensor with a sub-pT resolution using a resonating transmission line-type sensor element since high impedance change can be obtained with such a sensor. The CoNbZr film was deposited by RF sputtering, and a low anisotropy field of 0.8 Oe was applied by annealing. The CoNbZr film thickness of 4 micro m was found to be the optimum value by which to obtain the highest impedance change (dZ/dH). Carrier current flows in the Cu meander pattern, not in CoNbZr film, so the sensor is different from conventional GMI senors in that point. A small AC magnetic field was applied to the sensor element and a very small AM signal was detected using a carrier suppressing circuit. The experiments were carried out in a magnetically shielded room. A resolution of 0.7pT per square root Hz was obtained at 501kHz. The detectable magnetic field was limited by the chaotic noise caused by nonlinear magnetic excitation. A resolution of about 2pT per squire root Hz was obtained at 1kHz and a resolution of about 80pT per square root Hz was obtained at 45Hz.

在室温下工作的高灵敏度磁场传感器有望实现非破坏性生物磁测量（例如 MCG 或 MEG）。高频载波型传感器具有高灵敏度的潜力，如 SQUID（超导量子干涉装置）。在本研究中，我们使用谐振传输线型传感器元件开发了一种具有亚 pT 分辨率的非常灵敏的高频载波型磁场传感器，因为这种传感器可以获得高阻抗变化。通过射频溅射沉积CoNbZr薄膜，并通过退火施加0.8 Oe的低各向异性场。发现4微米的CoNbZr膜厚度是获得最高阻抗变化(dZ/dH)的最佳值。载流子电流在 Cu 蜿蜒图案中流动，而不是在 CoNbZr 薄膜中流动，因此该传感器在这一点上与传统的 GMI 传感器不同。对传感器元件施加一个小的交流磁场，并使用载流子抑制电路检测到非常小的 AM 信号。实验在磁屏蔽室中进行。在 501kHz 时获得每平方根 Hz 0.7pT 的分辨率。可检测的磁场受到非线性磁激励引起的混沌噪声的限制。在 1kHz 时获得每平方根 Hz 约 2pT 的分辨率，在 45Hz 时获得每平方根 Hz 约 80pT 的分辨率。