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Ferroelectric thin films are beginning to see wide-ranging applications, for example in multilayer capacitors, nonvolatile FeRAMs, and nanoactuators. Here, we explain how the fast molecular dynamics (MD) method for simulating a first-principles effective Hamiltonian can be applied to study ferroelectric thin-film capacitor structures with short-circuited electrodes or external electric fields. This new MD method can simulate perovskite-type ferroelectric thin-film capacitors with dead layers and consequent depolarization fields. You can download this simulator from http://loto.sf.net/feram/ .

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We have developed thin film capacitor embedded printed wiring board with high capacitance density (>40 nF/cm2). The thin film was fabricated by coating barium titanate (BaTiO3) nanoparticles mono-dispersed in suspension. We have investigated preparing thin films with higher packing density of nanoparticles because dielectric properties of thin film were affected by packing density of nanoparticles. We report the effect of particle size, particle distribution, and repulsive forces acted among nanoparticles on packing density of particles in the film at this meeting.

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To realize high performance and miniaturization of LTCC modules, thin-film ceramic capacitor(TFCC)formed directly on LTCC substrate with multi-terminal structures bonding directly with BGA package or WL-CSP was proposed. The TFCC was prepared using low cost aero-sol CVD(AS-CVD)method for SrTiO3(STO)dielectric thin film formation and Ag sputtering thin films as electrodes. The Ag/STO/Ag TFCC with STO thickness of about 0.5um, formed directly on as-fired LTCC substrate showed stable electric properties of capacitance density of 40 nF/cm2, dielectric loss <1% (1kHz-1MHz) and leakage current of 0.1uA/cm2 at 30VDC.

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BiFeO3 thin film has gathered much attention as it shows multiferroic property such as feroelectric and ferromagnetic and has giant polarization. We have prepared the BiFeO3 thin films by PLD and CSD methods, analyzed crystalline property, and studied various properties of ferrroelectric, pizoeletric and magnetic characteristics and theoretical analysis of electronic structure. Generally, BiFeO3 tin films show large leakage current and so is difficult to obtain dielectric characteristics. We ave succeeded in suppressing the leakage current by optimizing deposition condition such as oxygen pressure, Bi/Fe ratio, substrate selection and substituion of element for Bi and/or Fe sites. Resultantly, good ferroelectric and magnetic properties have been sucessfully obtained.

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Aluminum nitride (AlN) has emerged as an important material due to its outstanding electrical and mechanical properties. Aluminum nitride is applicable for heat sink, semiconductor equipment and several structural and electrical applications. Aluminum nitride has hexagonal and cubic structures. Cubic AlN (c-AlN) is a metastable structure and an unexplored material whose properties may be quite different from those of wurtzite AlN. Synthesis of c-AlN is more difficult than h-AlN because it is metastable phase. In this study c-AlN based coatings were fabricated through the nitridation reaction between Al feedstock powders and N2 plasma in Atmospheric Plasma Spray (APS) process. The influence of changing the particle size of Al feedstock powders on nitriding rate was investigated in this study by using three different particle sizes of commercial Al powders (with average particle sizes of 30, 15 and 3 micron). The results showed that cubic AlN based coating was fabricated through nitriding of Al powder in APS process. The nitriding reaction was enhanced by using smaller particle size of Al powers that the fine particles react easier with N2 plasma than larger particles. However spraying of fine particles was more difficult than larger particles and the fabricated coating incase of finer particles have heterogeneous structure.

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The objective of our research is the establishment of formula about frequency dependence of electro-optic effect. For the first step, we measured the electro-optic effect and piezoelectric displacement and analyzed them. We measured the electro-optic coefficient and piezoelectric displacement of rectangular LiNbO3(LN) single crystal. When only considering the change of light path length, the calculated electro-optic constant disagree with measured one. When considering the change of light path length and photo-elastic effect, the calculated electro-optic constant agree with measured one. Therefore, two effects of piezoelectric displacement are affected to electro-optic effect. One is the change of light path length, and the other is photo-elastic effect. And, the photo-elastic effect is more effective for the electro-optic effect than the change of light pass length. Considering these two parameters, we analysis the electro-optic effect near resonance frequency.

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Zinc oxide powders with plate-like, nut-like, spherical and nano-screws superstructures were prepared via soft solution route. The thin film of ZnO could also be produced directly on the substrates. The zinc oxide thin film with nano-screws superstructures was composed with visible-light responsive nitrogen doped titania nano-particles successfully. The ZnO nano-screws/TiO2-xNy composite film showed excellent photocatalytic deNOx ability and quantum efficiency.

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The Advanced Ceramic Reactor Project aims to realize novel high performance electrochemical reactor modules as micro-SOFCs, reversible cells and environmental purifying modules.

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Co oxides are well known as sintering aids for ceramics. Many reports have shown that the addition of cobalt compounds as a sintering aid enhances the sintering characteristics of ceria and zirconia. However, few papers have been discussed about the enhanced sintering mechanisms of the electrolytes with Co addition. In this study, we discuss the sintering mechanisms of Ce_0.9Gd_0.1O_1.95 (CGO) and Zr_0.79Sc_0.2Ce_0.01O_1.9 electrolytes with CoO addition using Synchrotron X-ray diffraction measurements.

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LSM-polymer composite particles, in which the polymer surface was coated with the LSM particles, were prepared in the mixed suspensions. By using the composite particles, porous cathode films for SOFC were prepared by screen-print method. Firing the green films of the composites gave a fairy porous structure consisting of a size-controlled pores originated from the polymer beads.

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The structure of anode was examined for reducing the operating temperature of SOFC to below 800 C. In the previous work, we reported a three-dimensionally ordered macroporous (3DOM) structure was effective for reducing the polarization resistance of anode. In this study, the size effect of 3DOM pore was investigated for further improvement of cell performance.

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Solid oxide fuel cells (SOFCs) have been developed more than 40 year, because SOFCs are respected to obtain high energy conversion efficiency and an excellent long stability. Many types of SOFCs as a tubular type and a plate plat type have been developed and 100~200 kW class SOFCs by Westinghouse Electric were tested to result in an excellent performance. However, SOFCs have not commercialized yet. In this talk, a prospect of SOFC will be discussed in a view point of the cost performance of the SOFC system.

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Steam electrolysis was carried out using a micro tubular ceramic reactor which has the cell configurations as follows; LSCF+CGO/CGO/ScSZ/Ni+ScSZ anode supporting tube. 10%H₂+Ar mixture gas was used as steam carrier gas, and 12-60% steam was supplied to inside of the ceramic reactors. The cell voltage 1.37 V at 0.5 A/cm² under 18% steam concentration was observed at 923K The heat generation from low current density was observed by electro-chemical technique. Voids and incursion of Zr were confirmed in CGO buffer layer. Such factors nearby surface probably caused increase in the ohmic resistance and electrode over potential.

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It is important to develop gas-solid reactions technology which makes it possible for the high removal performance of pollutants, the reduction of waste water and heat loss. In an integrated coal gasification power generation (IGCC), the development of the hot gas cleaning technology with gas-solid reactions has been expected to get higher thermal efficiency. In this report, the desulfurization, the halides removal and the mercury removal technology developed in our institute are introduced.

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