Three-dimensional analysis of magnetization distribution by MFM and electron holography

本研究计划的目的是发展一种新的技术，揭示三维磁化分布及其应用于纳米结构磁性材料。将电子全息术与磁力显微术相结合，可以同时观察面内磁通分量和近似垂直于样品箔面的杂散磁场，作为本课题的一项成果，我们建立了一种计算机模拟技术，通过该技术可以得到全息结果（即，磁通量的信息）可以被转换为薄箔样品中的磁化分布。MFM观测进行了相同的标本的全息研究，因此，磁化强度分布在三维显示。事实上，设计的方法被应用于磁记录系统和其他磁性材料。我们还开发了一种独特的方法，通过使用尖锐的磁针施加磁场-磁针产生近1 T的磁场，这是足够大的，用于在透射电子显微镜内进行原位观察的磁化过程。在研究期间取得了许多重要成果，并发表在主要期刊上，如Phys. Rev. Lett.，Appl.Phys.Lett.，应用物理学杂志，等

The aim of this research project is to develop a new technique that reveals a magnetization distribution in three-dimension and its application to nanostructured magnetic materials. Electron holography is combined with MFM (magnetic force microscopy) in ordered to observe both the in-plane component of magnetic flux and the stray magnetic field that is approximately perpendicular to the foil plane of the specimen.As an achievement in this project, we have established a computer simulation technique, by which a holographic result (i.e., information of magnetic flux) can be converted to a magnetization distribution in a thin-foiled specimen. MFM observations were conducted for the same specimen as that of the holography study ; therefore, the magnetization distribution was revealed in three-dimension. In fact the devised method was applied to magnetic recording systems and other magnetic materials. We have also developed a unique method to apply a magnetic field by using a sharpened magnetic needle-the needle produces a magnetic field near 1T, which is large enough for performing in situ observations of a magnetization process within a transmission electron microscope. Many important results were obtained within the research period, and they were published in major journals such as Phys.Rev.Lett., Appl.Phys.Lett., J.Appl.Phys., etc.