Development of a new method of electric/magnetic-filed measurementin a transmission electron microscope

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Two well known methods are often used to observe the electric/magnetic field distribution in a transmission electron microscope (TEM). The first one is electron holography, which requires a very expensive field-emission gun TEM (FEG TEM). The other one is Lorentz microscopy Though the latter method can be performed in a conventional TEM, the image in the Fresnel mode is obtained in defocused condition and, the image in the Foucault mode is not suitable for quantitative analysis.During in-situ electron holography experiments, we found a distortion of the image of the selected area diffraction (SAD) aperture in the very low magnification mode, celled "Low Mag" mode, while applying an external electrostatic potential to the specimen An analysis using geometrical optics for this phenomenon suggests that the distortion of the image can be correlated to the deflection of the electron beam by the electrostatic field at the level of a specimen. This method can be applied to the observation of … More the electric/magnetic field distribution by a conventional TEM without any additional apparatus.Geometrical electron optics of the shadow image distortion due to electric field in a conventional TEM has been analyzed, and the optical parameters to estimate the field strength have been determined in the system not only for the objective lens and the intermediate lens but also for the condenser lenses. The electrostatic potential distribution has been calculated along the electron beam passage and then compared to the observed value. The result shows that the integral of the horizontal part of electrostatic field can be measured quantitatively.The method we have developed has also been applied in some real materials.For example, a half cut Cu mesh with carton film fixed to the electrode at the specimen position has been observed. The 2D-maps showing the difference of the local field distribution has teen observed in the semicircle holes with and without the conductive carbon film which normalized the field in the hole. The whole shifts of the shadow image of the grid shaped aperture correspond to the field strength upper part of the specimen Separate detection of local field distribution at the specimen position and upper/lower part of the specimen is suggested. The electric field distribution around a FEG-emitter tip has also been observed by using our method.Through our research, several techniques to built the electrodes on to the side entry holder fir the TEM allowed us to observe the ceramics material, i.e., ceria-zirconia ceramics, in a high resolution condition at an elevated temperature. The suggested development of our technique as the results of this research will allow us to observe the atomistic mechanism of the nano-gap devices near future. Less