高灵敏响应近零微弱外磁场的磁敏新材料及机理研究

项目名称： 高灵敏响应近零微弱外磁场的磁敏新材料及机理研究

项目编号： No.50871104

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 方允樟

作者单位： 浙江师范大学

项目金额： 40万元

中文摘要： 本项目对FeCo基非晶合金薄带中观察到的一种对近零磁场高灵敏响应（2440%/安o每米）的新型巨磁阻抗效应- - 尖刺巨磁阻抗效应的机理及相关材料制备工艺进行了研究。研究结果表明，尖刺巨磁阻抗效应只存在于具有芯状复合结构的非晶薄带中，所谓芯状复合结构，是指芯部为被沿纵向定向偏析的富Nb-B区分割的具有纵向易磁化结构的非晶多形相变体，而外壳层具有横向易磁化结构的准铸态非晶体，并且，在内芯与外壳层之间存在过渡层。这种芯状非晶复合结构的合金薄带是由气流中电流退火的专门工艺（退火电流与气流及样品尺寸相匹配时）制得的，气流使样品在电流退火过程中形成芯部与外壳层之间的温差，芯部与外壳层间的温差及温差引起的应力两个因素共同作用，导致芯部与外壳层产生了不同的非晶多形相变，从而形成了芯状非晶复合结构。 尖刺巨磁阻抗效应实现了巨磁阻抗效应灵敏区向零磁场的逼近，有望开发对近零微弱磁场敏感的新型磁敏传感器，因此本项目的研究结果对于设计新型磁敏传感器具有现实意义；本项目揭示的非晶复合结构特征，对于新型非晶合金材料的开发具有重要的指导意义；本项目揭示的软磁合金非晶多形相变行为，对于非晶多形相变理论是一种有益的补充。

中文关键词： 软磁非晶；巨磁阻抗效应；复合结构；非晶多形相变；电流退火。

英文摘要： In the project, through the observation of the thin strip of FeCo-based amorphous alloy, the mechanism and material preparation process for a new kind of giant magneto-impedance effect (i.e., spiny giant magneto-impedance effect) which has a highly sensitive response to the near-zero magnetic field (2440%/Aoper meter) are studied. The research results show that the spiny giant magneto-impedance effect exists only in the amorphous thin strip of the core-like composite structure. The so-called core-like composite structure refers to the amorphous polymorphic phase body variant with a longitudinal magnetization structure. The core is divided by rich Nb-B area with orientation segregation along the longitudinal direction, and the outer shell has quasi-cast amorphous with transverse magnetization structure, and there is a transition layer between the core and shell layer. The alloy thin strip of core-like amorphous composite structure is obtained from the specialized process of the current annealing in air flow (annealing current matches with the air flow and sample size). The air flow will cause the temperature difference between the core and outer shell in the current annealing process of samples. Due to the temperature difference between the core and outer shell and stress caused by temperature difference, the different amorphous polymorphic phase change will be formed between the core and outer shell layer, thus forming a core-like amorphous composite structure. The spiny giant magneto-impedance effect achieves the approximation of sensitive area of giant magneto-impedance to the zero magnetic field, and it is expected to develop a new type of magnetic sensor which is sensitive to the near-zero weak magnetic field. Therefore, the research results of this project have practical significance for the design of new magnetic sensors; the features of amorphous composite structure revealed in this project have an important guiding significance for the development of new amorphous alloy material; the amorphous polymorphic phase change property of soft magnetic alloy revealed in this project is a useful supplement to the amorphous polymorphic phase change theory.

英文关键词： Soft magnetic amorphous alloy; Giant magnito-impedance effect; Composite struction; Amorphous polymorphic phase transition；Current annealing.