Recent development of computer technology has made possible to analyze huge datasets statistically and extract practically useful information, which is called ‘big-data analysis’. In materials science field, this type of approach has been in fashion in these two or three years. However, this approach is powerful with huge datasets, which are not fully supplied in materials science. The author has developed a few techniques to complement the shortage of numerical data that can be input directly to the computer, which are briefly reported in this article.

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Atom probe tomography (APT) is a three-dimensional (3D) analysis technique employed in science and engineering, offering information on the chemical compositions and atomic-scale structures of materials. A new technique called laser-assisted APT has been developed, in which a pulsed laser is used as a trigger for field evaporation instead of a pulsed high voltage (HV), allowing analysis of low-conductivity materials. However, in laser-assisted APT, the sample shape changes from the hemisphere to the non-hemisphere during measurement, which degrades the reconstruction accuracy. Here, to clarify the cause of sample deformation and improve the reconstruction accuracy, we studied the relationship between thermal diffusivity and the deformation degree. Our experimental results demonstrate that the sample deformation degree is inversely proportional to the thermal diffusivity, indicating that the sample heating by the irradiated pulsed laser is non-negligible and has a considerable impact on sample deformation in laser-assisted APT.

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We investigated the Auger depth profiling analysis for a magnetic head material of FeNi:5 nm/CoFeB:3 nm/FeNi:10 nm by the glancing-angle Ar ion beam sputtering method at an incident angle of 7 degree from the sample surface. In consequence, Ar ion acceleration voltage of 0.5 kV provided a depth profile result with a higher depth resolution, which represented a symmetrical structure of B with sharper interfaces as high as it can be evaluated quantitatively. In additional, Ar ion acceleration voltage of 3.0 kV also provided a similar symmetry structure of B in a shorter acquisition time. However, its depth resolution was lower than 0.5 kV. In contrast, as a result of measuring the same sample by atom probe tomography, one-dimensional concentration profile of B was artificially asymmetrical.

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The electronic states of indium zinc oxide (In-Zn-O: IZO), one of the transparent conductive oxides, were evaluated by x-ray photoelectron spectroscopy (XPS) and reflected electron energy loss spectroscopy (REELS). The carrier densities of the IZO films depending on the amount of oxygen vacancies are widely controlled by the oxygen flow ratios in the film deposition. In this study, we systematically investigated the relationship between the carrier densities and the electronic states of the IZO films.

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