基于GMI效应的薄膜地磁传感器噪声形成机理与优化设计研究

The Giant Magneto-impedance (GMI) effect thin-film magnetic sensor is one of high resolution geomagnetic sensor. It is very suitable for airborne magnetic survey with unmanned aerial vehicles (UAV) which require the geomagnetic sensor with high sensitivity, low power consumption and ease of miniaturization. In order to improve the signal to noise ratio of GMI sensor, based on the research of my National Natural Science Foundation of China(Youth Program), noise’s generative mechanism, film optimization design and noise suppression method of multilayer thin-film sensitive components are researched in this project. By analyzing the noise mechanism of thin-film GMI sensor, using micro-magnetic theory and Maxwell equations, factors of affecting the sensitive components’ noise is studied, also the magnetization process and magnetic domain motion of the multilayer film are simulated. The noise model of multilayer film structure coupling by multi-physics is established. By looking for the relationship between the magnetization process and the noise generated, investigating the effect of the hard magnetic bias layer on the magnetic domain movement of mul-tilayer thin-film, low noise film optimal design and noise suppression methods are proposed. A thin-film sensor noise test platform is built to test and analysis the noise characteristics of the multilayer film and to verify the effectiveness and superiority of film optimal design and noise suppression methods. This project will provide effective method to realize high-precision, high sensitivity, miniaturization geomagnetic sensor, which will have significant theoretical research and practical applications.

薄膜型巨磁阻抗效应（GMI）传感器是一种适合地磁场测量的高精度传感器，尤其能满足无人机航磁测量的微型化、响应速度快和低功耗等要求。为提高GMI传感器的性噪比，本项目在青年基金的基础上，研究传感器多层薄膜敏感元件的噪声产生机理，膜层优化设计方案和噪声抑制方法。通过分析GMI传感器的噪声来源，运用微磁学理论及Maxwell方程组，研究影响传感器敏感元件噪声产生的因素，模拟多层薄膜的磁畴运动和磁化过程；建立多物理场耦合作用下的多层薄膜结构的噪声模型，寻找磁化过程和噪声产生的相互关系，探讨硬磁偏置层对多层薄膜磁畴运动的影响，并提出低噪声膜层优化设计方案和噪声抑制方法；搭建GMI传感器噪声测试实验系统，测试分析多层薄膜敏感元件的噪声特性，验证膜层优化设计方案和噪声抑制方法的有效性和优越性。本项目的研究将为高精度、高灵敏度、微型化地磁场传感器的实现提供有效方法，具有重要的科学意义和应用价值。

基于GMI效应的薄膜地磁传感器噪声形成机理与优化设计研究主要围绕着多层GMI效应薄膜材料的机理研究、GMI传感器的噪声建模与制备和GMI效应的测试平台搭建三个方面开展工作，完成①分别对单层软磁薄膜、三明治结构和增强型三明治结构的多层软磁薄膜进行了建模仿真研究，制备了不同厚度和不同退火温度下的CoFeSiB多层薄膜，分析了CoFeSiB薄膜的厚度、退火温度及应力对其磁性能和GMI效应的影响；②建立了GMI传感器等效输入噪声模型并对模型进行了仿真，设计了快速响应的负反馈型GMI传感器，开展了巨磁阻抗传感器激励电路和信号检测电路的设计和制备工作，并初步开展了三轴GMI传感器的研制及其平面化工作；③针对GMI效应的测试需求，搭建了用于巨磁阻抗材料动态磁学特性测试的阻抗性能测试系统，开发了GMI应力测试平台，并实现了GMI传感器噪声测试平台。该课题的研究为后续GMI传感器应用的关键技术问题的完全解决提供了思路和方向。