交变力磁力显微镜动态成像技术的研究

近年来磁力显微镜(magnetic force microscopy,MFM)对动态磁场信号的测量与分析由于其特殊的工业要求和重要用途而受到广泛关注,本文旨在利用交变磁力对磁性探针的周期性调制发展一种交变力磁力显微镜技术,为磁信息存储工业等重要领域关键技术的发展提供新型的有力的工具.与目前标准MFM采用的设计思路不同,本文的关键在于合理利用MFM频率调制机理,优化设计MFM磁性探针,并且引入动态信号处理模块,实现对交变磁场信号的MFM成像.为达到这些目的,需要从理论上研究MFM探针的频率调制机理,并由实验上设计出动态信号提取模块,二者相辅结合优化设计出具有动态信号测试和分析能力的交变力磁力显微镜技术,由此来测量和解释纳米尺度磁畴结构.

Dynamic magnetic imaging by alternating force magnetic force microscopy

Recently, magnetic force microscope (MFM) for dynamic imaging of AC magnetic field has attracted considerable attention due to its potential applications and special requirements in industry. In this paper, we develop an alternating force MFM technique based on the frequency modulation of MFM tip oscillation, which provides a powerful tool for the development of key technologies in magnetic information storage industry. Different from conventional MFM, the main points of the present work are: 1) the investigation of the frequency-modulation phenomenon; 2) optimization of the MFM tip parameter, and introduction of the MFM signal processing apparatus; 3) observation of the AC magnetic field. For dynamic evaluation of AC magnetic field, we need to theoretically analyze the mechanical and magnetic properties of MFM tips, to technically develop the MFM signal processing apparatus, and to experimentally image the dynamic magnetic signals. Finally, we demonstrate the alternating force MFM technique, which can measure and analyze the nano-scale magnetic domain structures in advanced magnetic materials.
Keywords：magnetic force microscopynanomagnetismdynamic magnetismfrequency modulation