巨磁阻抗磁传感器研究进展

巨磁阻抗效应是指材料的交流阻抗在外加直流磁场的作用下发生显著变化的现象,利用该效应研制的巨磁阻抗磁传感器具有灵敏度高、体积小和功耗低等特点,具有巨大的应用前景.分析了巨磁阻抗磁传感器的研究现状,重点介绍了磁场传感器、电流传感器和生物传感器的工作原理和特性,并指出了其目前存在的问题和发展趋势.     

非晶纳米晶带材巨磁阻抗磁传感器特性分析

利用非晶纳米晶带材的巨磁阻抗(GMI)效应制备一种磁传感器,在输出最大值的特定频率下,研究与带材轴线平行和垂直方向磁场的输出特性.研究表明:在10.5 MHz附近的激励频率作用下,传感器输出取得最大值;传感器对平行磁场有一段高灵敏的线性工作区间,对垂直磁场不响应;纳米晶带材GMI磁传感器的灵敏度高达0.669 1 V/Oe,优于非晶带材制备器件的灵敏度0.1483 V/Oe.     

基于巨磁阻抗效应的微磁传感器研制

分析了巨磁阻抗敏感材料CoFeSiB非晶丝的特性,研制了磁传感器的硬件系统并对其进行了标定.试验表明:基于巨磁阻抗效应的新型微磁传感器具有灵敏度高、饱和磁场低、响应快和稳定性好等优点,具有较好的应用前景.     

基于非晶合金非对称巨磁阻抗效应的磁传感器设计

以CoFeNiSiB非晶合金薄带为敏感材料,测试分析了其软磁性能,经空气中磁场退火热处理,获得了较好的非对称巨磁阻抗效应(AGMI).以磁场退火处理后的非晶合金薄带为敏感元件,设计了AGMI磁传感器,并对其性能进行了开环和闭环测试.测试结果表明,开环条件下该传感器表现出较高的灵敏度;闭环条件下则表现出更好的线性度和更宽...     

基于巨磁阻抗效应的生物磁敏传感器技术

巨磁阻抗(GMI)生物传感器是基于一些非晶磁性材料的高灵敏巨磁阻抗效应的一类新型生物传感器,具有灵敏度高、稳定性好等特点,发展前景广阔.该文对巨磁阻抗生物传感器的工作原理、研究现状和应用前景进行了概述.     

一种磁传感器、量化鉴定磁码磁滞迴线特征的方法及自动柜员机、验钞机

一种磁传感器器、量化鉴定磁码磁滞迴线特征的方法以及具有该磁传感器的自动柜员机和验钞机。磁传感器设置有磁铁和磁敏感元件,磁敏感元件对磁铁磁化纸币中磁码而产生的磁码磁场大小及其方向进行响应,磁码在经过磁传感器表面时被磁铁磁化而完成完整的或者部分的磁滞迴线过程,并由磁传感器读取相应的磁化过程的信号再进行鉴定。本发明可以区分磁码属性并能够量化定义磁码的磁滞迴线特征,不依赖于磁码信号的强弱从而对检测间隙不敏感,故具有鉴定精确度高和鉴定稳定性好的特点。     

基于巨磁阻抗传感器的心磁信号检测的研究

针对心磁图仪诊断技术在临床上的普及需求和心磁图检查费用高昂的矛盾现状,提出了一种基于巨磁阻抗传感器的心磁信号采集和信号处理方法。该方法依据心磁信号和心电信号的相关性,通过以巨磁阻抗传感器为核心的数据采集电路,同步采集两种信号,并根据功率谱密度分析结果,自动调整带通滤波器的参数,使其能自适应跟踪心电信号的频率,滤除噪声信号,最后取得心磁信号。通过实验证明了该方案可在常温下准确测得心磁信号,且设备维护成本低,操作简单易行。     

基于CoFeNbSiB非晶丝巨磁阻抗效应的新型磁传感器

本文利用CoFeNbSiB非晶丝的巨磁阻抗（GMI）效应制作了一种新型微磁场传感器。该传感器尺寸小,灵敏度高,反应速度快,且不需要预热。文章中具体介绍了非晶丝的特性、传感器的硬件及软件设计。     

高灵敏巨磁阻抗小型磁传感器研制

利用单辊快淬法制备了CoFeNiSiB非晶薄带,经过400 A/mm2电流密度、20 ms脉冲间隔条件下的脉冲退火后具有较好的弱磁场灵敏性能.以该带材为磁敏材料,基于纵向驱动方式研制了一种巨磁阻抗(GMI)磁传感器,该磁传感器尺寸小、灵敏度高、频率响应好,±0.05 mT弱磁场范围内灵敏度可达到44.15 V/mT,在高灵敏度小型磁传感器领域具有较大的应用潜力.     

磁敏电阻无触点倾斜角传感器

本文介绍了利用电阻值随外界磁场变化而改变的磁敏电阻作为敏感元件,采用自重摆驱动永磁体转动,使永磁体与两个差动联结的ＭＲ元件相对覆盖面积变化,即磁通量改变,导致输出电压信号的变化,据此开发出ＷＴＨ系列无触点倾斜角传感器。该产品可广泛用于需要使用寿命长,工作频繁,可在水,油,粉尘,等多种恶劣环境下长期使用的多种场合。     

A novel integrated microfluidic platform based on micro-magnetic sensor for magnetic bead manipulation and detection

We present a novel integrated microfluidic platform based on micro-magnetic sensor for manipulating and detecting magnetic beads (MB). A micro-spiral planar coil in MB manipulating system microfabricated by micro-electro-mechanical system technology is implemented to manipulate MB, and a giant magnetoimpedance (GMI) based micro-magnetic sensor is employed to detect the trapped MB. In our work, MB can be efficiently trapped by trapping force generated from micro-coil in microchannel. Next, trapped MB are detected by the changing ratio of impedance, as well as the variation of resistance and reactance in GMI sensor for trapped MB induce weak stray magnetic field under the magnetization by external magnetic field. The maximum difference of GMI ratio between with beads condition and without beads condition is 4.0% at the optimum driving frequency of 20 MHz under the external magnetic field of 15 Oe, and resistance ratio varies more significantly than reactance ratio. In comparison with traditional MB detecting methods by GMI sensor, the integrated microfluidic platform based on GMI sensor can not only manipulate and detect MB signal sensitively, but also enhance detection efficiency and decrease the experiment errors. Furthermore, this platform avoids contamination from the solutions in chemically reactive layers and reduces assay time in future biomarker detection. In our work, the microfluidic platform based on GMI sensor has potential applications in biomarker detection via MB manipulation and detection.     

交流电流对非晶带材AGMI传感时域特性影响分析

非对称巨磁阻抗(AGMI)效应可用于高灵敏传感器的研制.提出非晶带材AGMI效应的3种工作模式同时作用下的物理模型,以法拉第电磁感应定律和自由能最小化原则为基础,建立低频工作频率下的传感模型,推导AGMI效应传感用输出电压的数学表达式,数值计算分析了交流电流强度变化时,输出电压的时域特性.研究结果表明:交流电流ia2较小时,输出电压呈现一次谐波特征,电流强度较大时,二次谐波占主导地位,强度幅值随ia2的增加而增加.研究结果对于高性能传感器的研制将具有重要的指导作用.     

交变磁场传感器法拉第屏蔽的研究

传感器在各种数据采集与检测系统中起着至关重要的作用.为了更有效的接收所需信号,我们除了进一步提高传感器本身的性能外,还要消除一些不必要的干扰.在检测低频交变磁场而且磁场信号极其微弱时,首先要选用高性能的交变磁场传感器将交变磁场信号转换为电信号,然后采用一系列的选频放大等电子技术,这样在两者之间就会产生不必要的电场耦合,影响对有用信号的准确测量,为了阻断该电场耦合,对交变磁场传感器采用法拉第屏蔽是不可或缺的重要环节.     

Fabrication of symmetrical meandering NiFe/Cu/NiFe film sensors and study of the effects of field direction and film thickness on giant magnetoimpedance

Sandwich NiFe/Cu/NiFe film sensors with symmetrical meandering structure are fabricated by Micro-Electro-Mechanical-System (MEMS) technology, the longitudinal, transverse, and perpendicular giant magnetoimpedance (GMI) effect have been investigated comprehensively. The correlation between film thickness and GMI effect are analyzed thoroughly. The experimental results show that the alternating current (AC) frequency of maximum GMI ratio decreases gradually with the increasing of magnetic layer thickness, but the conducting layer exhibits an opposite tendency. The NiFe and Cu layer both show a GMI ratio tendency from increasing to decreasing along with the increase of film thickness. It is observed the longitudinal, transverse and perpendicular GMI effect share a common characteristic: the AC frequency of maximum GMI ratio increases with the increase of external field intensity. However, there is a notable difference between them, it is demonstrated that the higher GMI ratio and sensitivity can be obtained in the longitudinal direction. The longitudinal GMI ratio reaches the peak value 191.2 % at f _AC = 6.5 MHz under H _L = 17 Oe in six turns sample with the Cu and NiFe thickness of 6 and 7 μm, respectively.     

旋转机械油路磨粒传感器的设计及仿真研究

设计一种应用于旋转机械油路检测系统的在线式油路磨粒传感器,其性能直接影响油路检测系统的监测结果。重点对传感器检测原理和结构特性等进行定性分析,根据电磁场原理和毕奥-萨伐尔定律等电磁学理论,推导并建立平衡线圈磁场分布数学模型以及传感器输出模型,研究影响传感器输出和磁场分布的几大因数,最后利用电磁场仿真软件对传感器平衡结构线圈的磁场分布进行仿真,为传感器的设计、优化改进提供了重要的理论依据。     

基于GMR的可辨向齿轮转速传感器的研制

设计了一种可辨向的巨磁阻（GMR）齿轮转速传感器。该齿轮转速传感器同时利用两路巨磁阻芯片作为敏感元件,分别采集并处理在齿轮转动过程中引起的磁场扰动信号,然后通过单片机对这两路信号进行运算处理,即可获得齿轮转动的速度及方向。所研制的可辨向巨磁阻齿轮转速传感器具有高精度、测量间隙大、便于使用等特点。     

磁流体传感器研究现状与发展趋势

磁流体是具有磁性和流动性的一种新型功能材料,以其独特的性能在传感器领域具有巨大的应用潜力。按照检测量的不同,全面介绍角度、体积、流量、磁场、加速度及其他磁流体传感器的成果及最新进展,分析各类磁流体传感器的工作原理。最后,分析目前研究中存在的一些问题,指出未来磁流体传感器研究的潜在发展趋势。     

The inspection of magnetic flux leakage from metal surface cracks by magneto-optical sensors

We investigated the feasibility of using magneto-optical sensors for measuring the magnetic leakage fields in non-destructive evaluation. We used magneto-optical garnet thin films as a sensor and the effect of crack dimension on the sensor's response were investigated via a simple Faraday rotation technique. Our results show that the sensor signal displays a linear increase as the length and depth of the cracks increase however; the change in crack width does not have a significant effect on the magnetic leakage field and the sensor's signal. This technique is capable of high resolution magnetic imaging of small surface cracks and thus has great potential for application in the magnetic flux leakage test industry.     

GMI sensitive element based on commercial Vitrovac amorphous ribbon

A very high giant magnetoimpedance (GMI) up to 420% and sensitivities up to 60%/Oe have been achieved in commercial Vitrovac^® 6025 Co₆₇Fe₄Mo_1.5Si_16.5B₁₁ amorphous ribbons. A relatively low frequency range of 0.5–10 MHz and driving current intensities between 1.5 and 15 mA in combination with high sensitivities, low GMI hysteresis with respect to external magnetic field make this material very attractive for low field sensing processes. Special treatments under load without heating result in additional stability and favorable noise to signal ratio. We explain these outstanding GMI properties taking into account extra uniform magnetization processes and longitudinal magnetic anisotropy. The complex study of the magnetic and GMI properties shows, that equilibrium of various parameters of GMI medium is an additional guarantee of stable functionality.