钴基非晶纳米丝的制备及其巨磁阻抗效应研究

Magnetic sensor based on giant magneto-impedance (GMI) effect of Co-based amorphous wires have a broad application prospect in the IT field due to their some advantages, such as high sensitivity, miniaturization and low loss. However, the research of amorphous soft-magnetic wire is limited because it is hard to prepare nano-wires due to the soft-magnetic alloy composition and preparation technology. Amorphous soft-magnetic wires with nanometer diameters are more suitable for application in the magnetic sensor with high frequency response and low loss, which conform to the overall development trend of sensor. In addition, the size of amorphous soft-magnetic wire is the key factor for GMI effect. But due to the limitation of wire diameter, the physical mechanism of GMI effect of cobalt-based amorphous nanowire is still unclear. This project intends to use the new Co-based bulk metallic glass alloy with large supercool region, first prepare the amorphous wires about 20 microns in diameter by the melt-extraction method, and using superplastic method to prepare nanometer amorphous wires. Then, we study the effect of temperature and draw speed on the diameter, length and surface quality of wires; also study the modulation methods and mechanism of GMI effect of Co-based amorphous nano-wires, lay a foundation for the research and development of high performance magnetic sensor.

基于钴基非晶丝巨磁阻抗（Giant magneto-impendance, GMI）效应的磁性传感器具有灵敏度高、微型化和低功耗等特点，在信息技术领域具有广阔应用前景。由于非晶软磁合金成分和制备工艺的限制，目前非晶软磁丝直径限于微米量级。直径在纳米量级的非晶软磁丝更有希望应用于高频响应、低功耗和集成化的磁性传感器，这符合传感器的整体发展趋势。尺寸效应是影响钴基非晶丝GMI效应的关键因素。但是目前样品尺寸对钴基非晶GMI效应研究存在争议，而且纳米丝材的GMI效应的物理机制尚不清楚。本项目拟利用我们新发现的具有超大过冷区间钴基非晶合金，首先采用熔融抽拉法制备直径约二十微米非晶丝，然后加热至过冷区间利用超塑性成形抽拉制备非晶纳米丝。研究加热温度和抽拉速度对非晶丝直径、长度和表面质量的影响；研究钴基非晶纳米丝GMI效应及其调控规律和形成机制，为高性能磁性传感器开发奠定基础。

基于钴基非晶丝巨磁阻抗（Giant magneto-impendance, GMI）效应的磁性传感器具有灵敏度高、微型化和低功耗等特点，在信息技术领域具有广阔应用前景。但是目前样品尺寸对钴基非晶GMI效应研究存在争议，而且纳米丝材的GMI效应的物理机制尚不清楚。本项目利用具有超大过冷区间钴基非晶合金制备出直径约260nm的非晶丝;研究了退火温度、超塑性拉伸、驱动频率、应力状态、钴基非晶合金纤维阵列和复合材料对巨磁阻抗效应影响规律; 研究了超塑性拉伸对钴基非晶纤维磁畴结构的影响、应力状态对钴基非晶纤维磁畴结构的影响，建立了相关模型成功解释了磁场演变和巨磁阻抗效应的关联性,探讨了钴基非晶微/纳米丝GMI效应及其调控规律和形成机制,为高性能磁性传感器开发奠定基础;此外, 开展了无稀土元素大过冷区间和强非晶形成能力钴基块体非晶合金研发工作和非晶软磁微丝和粉体电磁波吸收特性研究，为非晶软磁材料应用领域拓展和研究工作的深入进行奠定了基础。