He specializes in TEM researches using piezodriving nanoprobe technique introduced in TEM holder, Lorentz microscopy, and electron holography. In order to study a relationship between microstructure and physical properties of advanced materials, in-situ observations of microstructure, electrical conductivity, electric field and magnetic field were carried out by using the advanced TEM techniques. For instance, local conductivity measurement using the nanoprobe technique and electric field analysis by electron holography provided useful information to address essential problems of electrical conductivity in Ag-based conductive adhesive, i.e., composite material consists of insulating epoxy resin and metallic Ag particles. In addition to the analysis of electric properties, magnetic domain analysis of an itinerant-electron metamagnetic material, which exhibits first-order PM-FM phase transition and be known as a magnetic refrigerant, could be also achieved by carrying out in-situ Lorentz microscopy observation. As a fundamental research topic, such a magnetic domain analysis is important to study a nucleation process of PM-FM first-order magnetic phase transition. In this way, he focuses on TEM analysis of various kind of advanced materials in nanoscale by using advanced TEM techniques for characterizing physical properties, e.g., electrical conductivity, electric field, magnetism, and so on.

As a recent research topic, he promotes to develop a high-precision local conductivity measurement method, which are based on nanoprobing technologies using BN nanotube, carbon nanotube and advanced nanoscale materials. This developing method should be important to characterize electrical conductivity related with nanostructure such a defect and/or a contaminant in nanoscale-designed materials. Moreover, he also makes an effort to synthesize a metal-filled nanotubes with advanced functions, e.g., shape-memory effect, by using a precise electric current control technique. i.e., nanoprobing technique in TEM.

Keywords:

transmission electron microscopy/local conductivity measurement/nanotubes/electric field analysis/electron holography/Lorentz microscopy/Ag-based conductive adhesive/magnetic phase transformation/itinerant-electron metamagnetism