Crystalline titania (rutile) layers were prepared by thermal treatment of titanium substrates at various temperatures ranging from 100 to 800C. Ultraviolet (UV) light was irradiated on the crystalline titiania (rutile) layer under ambient conditions for 1 h. The UV-irradiated titanium substrates were soaked in a simulated body fluid (SBF, Kokubo solution) until 7 days in order to evaluate their in vitro apatite-forming ability. The UV-irradiated crystalline titania (rutile) layer induced bonelike apatite formation on their surface within 3 days. This suggested that ultraviolet irradiation enhanced the in vitro apatite-forming ability of the crystalline titania (rutile) layer except that they were highly crystalline, prepared due to heating at 800C.

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Effect of colloidal silica addition on the formation of porous spherical a -calcium orthophosphate (a -Ca3(PO4)2 ; a - TCP) agglomerates was examined in this research. The aqueous solutions containing the solution with 1.8 mol·dm-3 Ca(NO3)2, 1.2 mol dm-3 (NH4)2HPO4 and 0 ~ 0.4 mass% colloidal silica (primary particle size: 14 ~ 55 nm) were spray-pyrolyzed at 600ºC. After the solution containing colloidal silica (primary particle size: 24 nm) was spray-pyrolyzed at 600ºC, the resulting powder was further heat-treated at 1200ºC for 10 min. The crystalline phase of resulting powder was only a -TCP. This powder contained hollow spherical agglomerates with diameters of 1 ~ 11 um. After the calcium phosphate paste (CPP) with 50 mass% a -TCP was immersed into the simulated body fluid at 37 ºC for 7 d, the compressive strength was reduced down to 20 MPa, due to the increased porosity.

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We have successfully developed using hydroxyapatite (HAp) particles surface-modified with inositol phosphate (IP6). However, the apatite cement did not have a bioresorbability in the living body. Thus, we developed novel chelate-setting cement with bioresorbability using a-tricalcium phosphate (a-TCP) instead of the HAp as starting materials. The eight kinds of starting a-TCP powders were prepared by ball-milling in the range of 0 to 270 min using a Zr pod and beads. The pure a-TCP cements derived from the ball-milled powder for 120 min attained the highest compressive strength of 18 MPa in the case of the powder/liquid ratio = 1/0.40 [w/w].

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A new layered carbide, [Zr_1.97Y_0.03]Al₄C₅, has been synthesized and characterized by X-ray powder diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). The atom ratios [Zr : Y] were determined by EDX, and the crystal structure was refined from laboratory X-ray powder diffraction data (CuKα₁) using the Rietveld method. The crystal is trigonal (space group R3m, Z = 3) with lattice dimensions of a = 0.331934(4) nm, c = 4.09459(3) nm and V = 0.390701(7) nm³. The compound shows an intergrowth structure with NaCl-type [Zr_1.97Y_0.03C₃] thin slabs separated by Al₄C₃-type [AlC] layers. This material is isostructural with Zr₂[Al_3.56Si_0.44]C₅.

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Effects of O²⁻ or OH⁻-ion incorporation on the cage geometry in 12CaO7Al₂O₃ (C12A7) crystals are investigated by the Maximum Entropy Method (MEM)/Rietveld analyses of synchrotron powder X-ray diffraction data measured in SPring-8. The OH⁻ ion is located at the cage center and symmetrically attracts two axially-coordinated Ca ions, while, the O²⁻ ion is likely located at off-center positions and induces larger asymmetric Ca ion displacement.

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The crystal structures of SrAl₂O₄ at 1073 K and 1273 K were determined from conventional X-ray powder diffraction data using direct methods, and they were further refined by the combined use of Rietveld method and maximum-entropy method (MEM). The structure at 1273 K is hexagonal (space group P6322, Z = 2) with a = 0.51615(5) nm, c = 0.85408(3) nm and V = 0.19705(1) nm3. Final reliability indices were Rwp = 7.50% (S = Rwp /Re = 1.25), RB = 1.21% and RF = 1.58%. The three-dimensional electron density distribution image showed that the oxygen ions were split to occupy the lower symmetry sites. The orientational disorder of the SiO4 tetrahedra is consistent with that determined in Sr0.864Eu0.136Al2O4 and Ba0.6Sr0.4Al2O4 at ambient temperature.

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BaLn₂Mn₂O₇ has a Sr₃Ti₂O₇-type layered perovskite structure with double-block oxygen octahedra. In-situ transmission electron microscopy observation revealed that BaLn₂Mn₂O₇ undergoes several transitions upon heating. In the case of BaPr₂Mn₂O₇, the tetragonal P4₂/mnmphase was transformed into a tetragonal phase I4/mmm phase at 373 K by in-situ single X-ray diffractometory. At 1040K, split reflections appeared along the c-axis in which two phases were coexisted, and the transition was of the first order.

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Segregated dopants at grain boundary dramatically change the mechanical and electrical properties in materials. The knowledge of the behavior of these dopants is therefore a key for further material developments. Here, a Zr doped alumina (Al2O3) bicrystal was fabricated and the atomic structure of the grain boundary was characterized using scanning transmission electron microscopy (STEM). Zr was found to segregate to specific sites along the grain boundary, which were neighbored by Al columns of weak image intensity. First principles calculations and static lattice calculations revealed that the charge compensating Al vacancies are most stable in Al columns neighboring the location of the Zr sites. Multi-slice simulations of STEM images confirmed that Al columns containing vacancies exhibit a reduction in image intensity. These results give strong evidence that the associated Al vacancies are strongly influenced by the atomic site of Zr segregation.

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In the present study, we have made a theoretical approach based upon the first principles projector augmented wave (PAW) method to investigate the behavior of LaAlO3 and related perovskites under pressure. In addition to the conventional static total energy calculations, we have computed phonon states by using the direct method. The present calculations quantitatively well reproduce the experimentally observed phase transition pressure and the pressure dependence of phonon frequencies in LaAlO3, confirming the compound's exceptional behavior for the general rule. Further systematic calculations were made on a series of perovskites, providing a clue toward new general rule of displacive transitions.

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A sensor applying surface plasmon resonance(SPR) phenomenon can be detected a changing of refractive index in a space over gold film. The SPR-sensor uses to detect an interaction between biomolecules. An interaction between ceramic film and biomolecule will also be able to detect by inserting the ceramic film to the detecting space. The changing of refractive index is measured as a maximum angle of attenuated total reflection (SPR-angle). The SPR-angle can be calculated using Fresnel's equation. In this study, we made devices of SPR-sensor with ceramic films and analyzed an optical property of the films to SPR-angles comparing theoretical calculation.

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True density of amorphous carbon films deposited on the surface-plasmon-resonance (SPR) device was measured. An X-ray reflectivity analysis revealed that the density of the amorphous carbon films deposited by a radio frequency magnetron sputtering method and an electron cyclotron resonance plasma chemical vapor deposition method were 1.6 g/cm3 and 1.4 g/cm3, respectively. The SPR angle was shifted toward high value when the film density and the thickness increased.

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Carbon microcoil (CMC) can be easily extends or contacts under very small stress, and electrical parameters (L,C.R.Z,etc.) changes under the extending and contracting. Accordingly CMC/elastic resin elements are useful as highly sensitive tactile or proximity sensor elements. In this study, relationship between preparation conditions of CMC sensor element and sensing properties were examined. It was found that electrical resistivity of CMC(4vol%)/polysilicone element changed by 1,000 times under applied compressive stress of 0.1-0.2MPa. (tactile property). Furthermore, It was found that z(impedance) or L(inductance) of the element gradually changed under accessing a hand or metal (proximity property).

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A surface plasmon resonance (SPR) analysis uses to detect an interaction between biomolecles. We are applying the SPR analysis to detect an interaction between a ceramic film and a biomolecle. A problem of SPR analysis is that determine of the optical properties of the ceramic film are difficult due to effect many factors to the result of SPR analysis. An X-ray reflectivity analysis is able to solve the problem by determining the film thickness before SPR analysis. Then we could analyze optical properties for the ceramic film and detect a biomolecule on the film using SPR analysis

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To design dielectric materials for high temperature guaranteed nickel-electrode multilayer ceramic capacitors (Ni-MLCs), (Ba,Ca)TiO3-Rare earth-Mg based system was studied. By increasing Ca concentration till 10 mol% in (Ba,Ca)TiO3 based ceramics, the Curie temperature increased, and the temperature dependence of dielectric constant became stable. In addition, the reliability improved with increasing Ca concentration. It was considered that these characteristics are caused by the change of microstructure in the (Ba, Ca)TiO3 based ceramics. From these results, the (Ba,Ca)TiO3 based materials around Ca concentration 10 mol% will be expected as dielectric materials for high temperature guaranteed Ni-MLCs.

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The formation energies of intrinsic vacancies in cubic-BaTiO₃ were studied by first-principles calculation and compared with reported data for SrTiO₃. It was found that in the oxidizing condition the defect species having the lowest defect formation energy are V_Sr^2- +V_O²⁺ in SrTiO₃ and V_Ti^2- + V_O²⁺ in BaTiO₃ and the overall vacancy formation energy in BaTiO₃ is higher than in SrTiO₃.

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In the present study, we systematically studied the ferroelectric and dielectric aging effect of BaTiO3 single crystals doped with different ratio of acceptor K+ and donor F-. We found that hybrid-doped BaTiO3 showed obvious aging effect only when the concentration of the acceptor K+ is higher than that of the donor; when the donor F- is richer than the acceptor K, the K-F doped BaTiO3 showed almost no aging effect. Based on a defect chemistry analysis and the microscopic mechanism of the aging, the difference in the aging behavior of the two kinds of crystals is fully explained.

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It has been well known that in ferroelectrics, acceptor doping and donor doping lead to quite different effects on the ferroelectric aging. Acceptor doping results in strong aging effect, and donor doping results in weak aging effect which can be ignored. However, the study on hybrid doping is very limited. Here we report the aging phenomenon in Fe [acceptor dopant] and La [donor dopant] co-doped BaTiO3, with Fe fixed at 1mol% and La varied from 0.5mol% to 1.5mol%. We found that in Fe&La-BaTiO3, obvious aging phenomena [double P-E loops] can only be observed when Fe [acceptor dopant] is dominant. When La dopant is equal to or exceeds Fe dopant, there is no aging phenomenon observed. Finally, the reason was discussed and tentatively explained from the view of defect chemistry.

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Most ferroelectric materials exhibit aging effect (a time dependent change of physical properties) in their ferroelectric state; however, aging is not reported to exist in the paraelectric state. In this paper we report an unexpected finding: aging effect also exists in the paraelectric state of ferroelectric materials. We proposed a microscopic mechanism, which unifies both ferroelectric aging and paraelectric aging effect. The paraelectric aging may provide a good chance for understanding the role of defects in ferroelectrics, because paraelectric state has no spontaneous polarization and domain walls to complicate the interpretation.

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he chemical solution deposition method has been applied widely for multicomponent thin films. Generally, its high potential is attributable to the homogeneity of solutions. However, low affinity among conventional raw materials such as metalorganic compounds and organic solvents sometimes remains problematic. Tailoring the molecular structure of a liquid source and optimizing its solubility and reactivity for hydrolysis, condensation, and combustion would yield a precisely controlled composition, low-temperature crystallization, high phase purity, and uniform microstructure in thin and thick films deposited using the liquid sources. In particular, low-temperature crystallization is essential for integration of advanced ceramics such as ferroelectric thin films into silicon-based semiconductors and other substrates.

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Characterizations of layered MoO3 host with interlayer polyaniline (PANI), i.e. (PANI)xMoO3, have been carried out by means of XRD, TG, solid-state NMR, and XPS analyses. The guest organic components, i.e. PANI, are accommodated into MoO3 interlayers by ion-exchange process. From these detailed characterization studies, it is found that the interlayer PANI chains have non-proton-doped units as well as proton-doped units. Moreover, the (PANI)xMoO3 hybrids have enough interlayer spaces due to almost perpendicular orientation of benzene ring into PANI chains to the MoO3 layer. The (PANI)xMoO3 hybrids as gas sensors have a resistance drift problem, which should be solved for realizing practical applicable gas sensing devices. In this XPS study, it is revealed that the resistance drift is caused by adsorbing and desorbing oxygen molecules from the atmosphere.

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SnO₂ films were prepared by liquid phase deposition. The substrates were immersed in the aqueous solution of SnF₂ at 50 °C. The transmittance of the films prepared on quartz substrates is higher than 80 % in the UV-Vis region and the absorption spectra varied with the heat treatment at 300 °C in a different atmosphere. On the other hand, in-situ observation of the X-ray absorption spectra showed no significant change with the atmosphere.

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Nitride thin films with zinc blende / wurtzite type crystal structure were deposited by reactive sputtering of (Fe₇₀Co₃₀)_1-xAl_x composite target in nitrogen atmosphere. Ferromagnetic particles Fe₇₀Co₃₀ were precipitated and were decomposited by their thermal annealing at 500 degrees in the vacuum state. The electrical resistivity of external magnetic field of 0kOe is increased and the particle size is decreased with increasing Al volumes. As increasing Al volumes in the annealed film, the magnetoresistance ratio increased. The annealed film showed the largest magnetoresistance ratio of 0.06% at the composition of x=0.66.

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Bi-substituted yttrium iron garnet, Y3-xBixFe5O12 (Bi:YIG, x = 1, 1.5), films were prepared on Gd3Ga5O12 (111) substrates by a metal-organic decomposition (MOD) method to use as magneto-optical (MO) indicator films. Those films had the in-plane magnetic anisotropy and Faraday rotation as large as that of the single crystals. Magnetic recording marks were successfully observed using Y1.5Bi1.5Fe5O12 films with a thickness of 200 nm. The characteristics are suitable for MO indicator films to visualize a stray magnetic field strayed from a specimen with high resolution.

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