电场调控的磁电耦合巨磁阻抗传感器研究

Giant magnetoimpedance (GMI) effect with high sensitivity, small size and low cost, is a kind of high resolution of magnetic field detection technology which could be used in biological medicine, earth-magnetism navigation and some other interdiscipline subjects. With the rapid development of film technology, the size of magnetic sensors is project to micro/nano-scale, which turns to hot spot. This research is based on the fundamental understanding that transverse permeability plays an important role to GMI effect, therefore a newly developed technique that introducing the magnetoelectric is developed. Tensile mediated magnetoelectric is an effective method which is expected to regulate and enhance GMI effect by applied a voltage on piezoelectric substrate. Based on the magnetoelectric effect, the magnetization could be regulated by changing the magnetostriction, magnetic anisotropy of magnetic film and vibration mode of piezoelectric film. When the direction of magnetization is reoriented along the transverse, the GMI effect could be regulated and strengthened. Thus, this work is of much interest both for the improvement of GMI effect and for the development and application of GMI magnetic sensors.

巨磁阻抗（GMI）传感器具有灵敏度高、尺寸小、功耗低等优势，在生物医药、地磁导航等领域具有巨大的应用潜力。近年来，随着磁性传感器微型化、集成化的发展，薄膜型GMI传感器成为研究热点。由于薄膜GMI传感器存在调控难、效应弱的问题，因此本项目从“横向磁导率”影响GMI效应这一基本思路出发，通过应力传导的磁电耦合效应实现薄膜GMI效应的增强及电学调控。本项目从磁电耦合体系中磁性薄膜的磁致伸缩、各向异性及压电材料的振动模式等参数入手，调控Fe基软磁薄膜和压电材料的磁电耦合效应，实现电场对磁性薄膜磁化翻转的控制。当翻转方向能够沿“横向”时，将提高薄膜的横向磁导率，进而实现GMI效应的电调控。以上工作的开展，能够极大简化薄膜GMI效应的调控手段，提高薄膜GMI传感器的灵敏度，为薄膜GMI传感器的发展提供新的思路和方法。

磁电耦合型巨磁阻抗效应可以通过原位电场实现对磁性薄膜巨磁阻抗效应的调控，其原理是基于应力传导的磁电耦合效应。高灵敏度和原位可调的特点，使其可广泛应用于生物磁场检测、地磁导航等领域。本项目基于FeGa/PMN-PT体系开展研究工作，一方面，系统的探究了生长温度、厚度、衬底、激光功率密度等参数对薄膜结构及软磁特性的影响；制备了FeGa/Mn多层膜，获得了具有优异输运特性的Fe2MnGa赫斯勒合金；通过N掺杂，在400摄氏度下生长的FeGaN薄膜，饱和磁化强度达到了430emu/cc。另一方面，在不同取向的单晶PMN-PT上制备了具有面内单轴各向异性的FeGa薄膜，并通过电压调控，使其各向异性场最大可以达到270Oe，实现了该体系中FeGa薄膜的GMI曲线峰位大范围变化，该结果为研发磁电耦合型GMI传感器奠定了理论基础。最后，发展了碳基/铁磁复合材料体系的GMI特性，使得GMI材料体系向更轻薄的方向发展。