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Finding a novel lead-free piezoelectric and ferroelectric material is important issue because the lead will be prohibited to use in electronic devices in near future. Our aim in the present study is to investigate the morphotropic phase boundary [MPB] in the BiFeO₃-BiCoO₃ solid solution films. The XRD patterns of the BiFeO₃-BiCoO₃ solid solution films showed the complicated structural change with changing the composition, which indicates the possibility of the MPB in the BiFeO₃-BiCoO₃ solid solution. We will also discuss the ferroelectric properties.

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Tetragonal type of ferroelectric materials are attracted much interest because a large piezoelectric effect can be expected in a high tetragonality material. In term of a typical tetragonal ferroelectric material of BaTiO₃, the tetragonality is too low (c/a=1.01). In contrast, BiCoO₃ has high tetragonality of 1.27. In our aim is to fabricate the BaTiO₃-BiCoO₃ solid solution films and investigated their structure, ferroelectric and ferromagnetic properties.

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(K_0.47Na_0.47Sr_0.03)NbO₃ system thin films were deposited by PLD on Si crystal substrates. The rf-sputtering layer of RuO₂ and SrRuO₃ layer formed by PLD were employed as the lower electrodes. (K_0.47Na_0.47Sr_0.03)_XNbO₃ bulk targets (X=0.9-1.05) with 0.5-5% Mn additive were prepared, and the effects of Mn addition and influences of A/B ratio on the electrical properties of the deposited films were studied. The depositional conditions for the crystalline film formation at lower temperature were also investigated.

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Nano-sized barium titanate particles have prepared by sol-gel method. And barium titanate thin films have been prepared by coating the nano-sized barium titanate particles dispersed solution. In this study, in order to fabricate the film capacitor, we made barium titanate thin films(800nm) onto copper foil at low temperature, and the characteristic evaluation was carried out. Then, the dielectric constant was 21, and dielectric loss was 3%.

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Perovskite-type structure SrRuO₃ using thin film electrode of electronic components is known as high conductivity ceramics. This components is often connected, covered and protected by solder glasses. New solder glasses without lead and alkali elements are needed. In this study, a reaction between SrO-SiO₂-B₂O₃ glass and SrRuO₃ conductor was investigated by XRD. According to XRD, non-reaction was observed in the composite material.

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The relationship between occupied site of Pr³⁺ and luminescent properties for SrTiO₃:Pr³⁺, and the effect of Al addition on the properties were investigated. The photoluminescence (PL) spectra of SrTiO₃:Pr³⁺ and the variation of PL intensity versus Pr³⁺ content indicated that Pr³⁺ ions occupy both Sr and Ti site. In Al-added SrTiO₃: Pr 0.2%, the solid solution is formed when the Al content is up to 7% by the inner addition, in contrast, up to 0.5mol % by the outer addition. The strong enhancement of red PL intensity was then observed by Al addition of 0.5mol % for both cases. The comparison between dependencies of lattice parameter and PL intensities on the content of Al addition, indicate that the enhancement of red PL intensity is attributed to the substitution of Al for Ti, and the content of Pr³⁺ in Ti site decreases with the substitution of Al for Ti.

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The reaction between silica nano-particle and silane coupling agent was analyzed by gas chromatography, dynamic light scattering method, Raman spectroscopy and nuclear magnetic resonance spectroscopy. Additionally, an organic-inorganic hybrid material film was prepareted with the surface modified silica nano-particle and acrylic monomer.

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Barium titanate (BaTiO3, BTO) and barium strontium titanate ((Ba,Sr)TiO3, BSTO) inverse opal photonic crystals were synthesized by a process of self-assembly of polystyrene opal template in combination with electrophoretic deposition of crystalline nanoparticles from BTO and BSTO suspension. In this process, stable monodispersed suspension of BTO and BSTO nanoparticles was prepared by dispersing BTO and BSTO gel into a mixed solvent of 2-methoxyethanol and acethylacetone. Then the BTO and BSTO nanoparticles were infiltrated into the interstices of the opal template formed by monodisperse polystyrene microspheres by electrophoretic deposition, and then Polystyrene template was removed by calcining the specimen at a final temperature of 500oC. SEM images show that the Lead-free ferroelectric inverse opals possess a face-centered cubic (fcc) structure with center to center distant of the air spheres between 250~330 nm. photonic bandgaps in the visible range (500~580nm)are observed from reflection spectra of the samples. Such Lead-free ferroelectric inverse opals as photonic crystals should be of importance in device applications.

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The photoelasticity of SnO-P₂O₅ (SP) glasses was studied using the photoelastic method which is the most practical way to know the stress of materials. Transparent SnO-P2O5 glasses were prepared by melting at over 880 ^oC with carbon crucibles. The photoelastic constant (PEC) was measured with the difference of retardation using frequency stabilized transverse Zeeman laser. In the case of SnO-P₂O₅ glasses with 62 - 72 mol% SnO, the PEC is about 0.94 - 1.90 x 10^-12 Pa^-1 at 633nm and increases with increasing SnO concentration.

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Sol-gel-derived bioactive SiO2-CaO-P2O5 glass layer was prepared. After soaked in simulated body fluid (SBF), a flower-like structure was formed on the glass layer surface. With the increasing soaking time in SBF solution, the SiO2-CaO-P2O5 glass layer showed enhanced superhydrophilicity and weakened superoleophilicity behaviors. The different special surface composition and morphology induced by the various soaking time in SBF solution are the two important aspects that is responsible for such unusual properties.

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