【作者】 叶晶；

【导师】 方健文； 彭保进；

【作者基本信息】 浙江师范大学 ， 光学， 2007， 硕士

【摘要】 巨磁阻抗(Giant Magneto-impedance,GMI)效应即材料交流阻抗随外加磁场变化可显著改变的物理效应。利用巨磁阻抗效应制作的磁传感器在工程控制方面拥有广阔的应用前景。薄膜GMI传感器适合半导体电路的集成并可批量生产,能大大降低生产成本,因此研究软磁薄膜材料中的巨磁阻抗效应具有重要的价值。本文主要做了两方面的工作,一是采用新方法制备了巨磁阻抗薄膜并证明其可行性,二是设计制作了一套简易的巨磁阻抗效应检测系统。这两方面都是从经济实用的角度出发,目的是为了尽量降低成本。目前,在制备具有巨磁阻抗效应的单层和多层膜的方法中皆用磁控溅射法,还未有文献提及过利用真空蒸镀法制备的实用有效的方法。但是磁溅射镀膜机价格昂贵,所以很难普及。真空蒸镀镀膜机价格相对低很多,所以利用真空蒸镀法制备巨磁阻抗薄膜,可使这类膜的生产成本大幅度降低。本文提出了利用真空蒸镀法制备具有巨磁阻抗效应的FeSiB薄膜的实用可行方法,克服了目前利用蒸镀法制备该类薄膜普遍存在的成分比例难以控制,膜层附着力弱、致密性和均匀性差等缺点。首先,采用真空蒸镀法,解决了成膜不牢固的问题,在玻璃基片上制备了具有巨磁阻抗效应的单层膜。经过改变驱动电流方向和外磁场方向,得到了四种测量巨磁阻抗效应的方式。但是只有当外加磁场和单轴磁各向异性方向垂直时才有巨磁阻抗效应出现。比较制备得到的磁各向同性和磁各向异性薄膜的纵向和横向的巨磁阻抗效应,说明了各向异性在巨磁阻抗效应中的重要性及本实验采用加恒定磁场的方法产生各向异性的可行性。证明了用真空蒸镀法能够制备巨磁阻抗薄膜材料。其次,利用真空蒸镀的方法制备了FeSiB/Cu/FeSiB多层膜,检测其巨磁阻抗效应,给出相应测量结果。并讨论了夹心膜导电层的厚度对巨磁阻抗效应的影响。最后,提出一种蒸镀合金材料的新方法,即根据合金各成分熔沸点的不同,事先调整合金比例,使成膜后达到理想效果。给出FeSiB合金的三种调整比例及成膜后的成分比例,并对按三种不同比例制备的FeSiB/Cu/FeSiB多层膜检测其巨磁阻抗效应,证明了新方法的可行性。与此同时,针对美国Agilent公司生产的磁阻抗测量仪价格非常昂贵,我们重新设计、改进和制作了一套基于电脑和信号发生器,稳定可靠,并能够实时显示的GMI测量系统。该系统能直接描绘出GMI比随外加磁场的变化情况。本文重点介绍改进测试的过程、原理以及参数选择的问题、操作过程和可靠性的分析。测试结果表明,该系统稳定可靠,实现了实时显示,且价格实惠,已经基本满足测定各类巨磁阻抗材料的要求。尤其适合学生实验。更多还原

【Abstract】 Giant magneto-impedance effect is a physical effect that the transformation of alternating current impedance of material is obvious according to the change of external magnetic field. The magnetic sensors using giant magneto-impedance effect has broad prospects In engineering control field. Thin film sensors are advantageous on mass-production and integration of semiconductor circuits, so it is highly valuable to study the GMI effect in soft magnetic film materials. This paper mainly presents the work of two. The first is to introduce a new method of preparing giant magneto-impedance thin film. The second is to describe the design of a new detection system for GMI. Both are based on practical and economical factors. Most reducing cost is the main purpose.At present, the methods of preparing monolayer and multilayer films with GMI effect are mainly by magnetron sputtering. There is no text present the effective way by vacuum evaporation. Because of the high price of the magnetron sputtering coating system, it is hard to popularize. Comparatively, the coating system of vacuum evaporation is very cheap. So the preparation of giant magneto-impedance materials by vacuum evaporation can reduce the productive cost largely. This text presents a practical and feasible method of preparing FeSiB film with GMI effect and overcomes several disadvantages of preparing this kind of films, such as the difficult of controlling the composition ratio, weak film adherence, the poor densification and uniformity, and so on. By solving the problem of no-stable film, the monolayer Film with giant magneto-impedance effect was prepared in glass substrate by vacuum evaporation. Via to transfer the direction of drive current and external magnetic field, four modes of measuring giant magneto-impedance effect were obtained. By comparing, it is found that only if the direction of external magnetic field and uniaxial magnetic anisotropy is apeak, there is the obvious appearance of GMI effect. By comparing the GMI effect of magnetic isotropic and magnetic anisotropy, it is proved that anisotropy is very important in GMI effect and that the feasibility of producing anisotropy by imposing invariable magnetic field in experiment. So the feasibility of preparing the material which have giant magneto-impedance effect by vacuum evaporation was proved.At the same time, considering the price of magnetic impedance measuring instrument produced by Agilent from the United States is very high, we re-design, improve and produce a stable and reliable measurement system for GMI. It based on computer and signal generator, ran stably and reliably, and achieved real-time display! The system can trace out the GMI ratio directly. This paper focuses on the testing process of improvement, principles, parameters selection, process of operation and the analysis of reliability. Testing results show that the system is stable and reliable, real-time display, and affordable. It has basically met the requirements for various materials of giant magneto-impedance. Particularly it is suitable for student’s experiment.更多还原