Key Engineering Materials Vol. 596

Abstract: Diffraction intensities of a single crystal of Fe₃Pt alloy have been measured by using white X-rays of synchrotron radiation. The observed intensities have been compared with the calculated ones for fundamental and superlattice reflections. By normalizing the calculated intensities of fundamental reflections to the observed ones and evaluating the ratio of the observed intensity of superlattice reflection to the calculated ones, we have estimated the order parameter as 0.82±0.03. The obtained order parameter has been applied to an analysis of the X-ray magnetic diffraction data to estimate the spin moment of Fe and Pt atoms in this alloy.

Abstract: Magnetic Compton profiles (MCPs) of Co/Au multilayers have been measured and analyzed by DV-Xα cluster model calculations from a viewpoint of perpendicular magnetic anisotropy (PMA). The PMA and the MCPs are discussed for the presently obtained results for Co/Au, along with the previously obtained results for Co/Pd and Co/Pt. A Co/Au multilayer shows a weak PMA which is caused by |m|=1 states of Co 3d electrons at a smooth Co/Au interface. The increase of the interface-to-volume ratio plays the main role in determining the perpendicular anisotropy in Co/Au multilayers. The strain of a Co layer can have a secondary role in determining the magnetic anisotropy in Co/Au multilayers, although the strain dominates PMA in the case of Co/Pd and Co/Pt multilayers.

Abstract: Thin-film samples of the lithium ionic conductor Li₂SiO₃ (LSO) were deposited on an A-plane sapphire substrate via the pulsed laser deposition (PLD) method, and the irreversible temperature dependence of the ionic conductivity in the thin-film samples was studied. Via transmission electron microscopy (TEM) observations of annealed LSO thin-film, it was found that the as-prepared LSO thin-film was amorphous over the temperature range T 490 K, and that nanocrystals existed in the annealed LSO thin-film in the temperature range T 550 K. Further more, it was clarified the irreversible temperature dependence of the ionic conductivity is due to the generation of nanocrystals.

Abstract: Electrical properties of SnS films deposited by a thermal evaporation method have been investigated using the resistivity and thermopower measurements. The SnS films show p-type conduction at room temperature, and electrical activation energy of ~0.3 eV. Resistivity and Seebeck coefficient at room temperature were ~4×10¹ Ωm and +0.2 mV/K for as-deposited sample. The resistivity decreased ~1×10⁰ Ω·m and the Seebeck coefficient increased +0.27 mV/K when the sample was annealed at 400 °C. Crystallization and structural change cause the improvement of electronic transport with annealing treatment.

Abstract: La_1-xBa_xCoO₃ single crystals were grown from KOH melt at 873 K under H₂O/O₂ mixed gas flow. The grown crystals had a parallelepiped form with the edges of about 60 μm. Streaks indicating twin boundaries were observed on the surface planes of the crystals. The crystals showed magnetic anisotropy and anomalous MH hysteresis loops. The magnetocrystalline anisotropy and coupling of ferroelasticity and ferromagnetism were discussed based on the magnetic properties.

Abstract: In order to obtain information about the structure of a typical Li⁺-ion conducting glass of (LiCl)_x(LiPO₃)_1-x, ³¹P MAS NMR measurements were performed for the glass samples with different LiCl compositions x from 0 to 0.4. NMR spectra of the samples indicated the existence of two kinds of P atoms; one is that within the-P-O-P-O-P-chain of LiPO₃, P(Q²), and the other is that at the ends of the chain, P(Q¹). The ratio of the amount of P(Q¹) to that of P(Q²) was observed to increase with the increment of x. The result shows that the addition of LiCl to the glass former of LiPO₃ changes the glass network structure by cutting P-O bonds in one-dimensional phosphate chain, and the increment of the Li⁺-ion conductivity with the increase of x is concluded to be brought not only by the increase of the amount of LiCl dissolved into the interstices between the phosphate glass networks but also by the dispersion of the phosphate glass network structure.

Abstract: In dye-sensitized solar cells (DSSCs) fabricated with azobenzene and azulene derivatives as the photosensitizing dyes, the replacement of the conventional I₃^-/I^- redox mediator with Br₃^-/Br^- redox mediator possessing more positive redox potential has been examined to improve open-circuit photovoltages (V_oc) of the cells. The cells with the Br₃^-/Br^- redox mediator exhibited high V_oc of ~0.8 V, resulting in higher light-to-electric energy conversion efficiencies (η) than the cells with the I₃^-/I^- redox mediator by a factor of 1.7 under the simulated sunlight irradiation (AM-1.5G, 100 mW cm^-2). The results indicate a high potential of the Br₃^-/Br^- redox mediator in DSSCs.

Abstract: Niobium modified titania samples were prepared by thermal reaction of titanium tetraisopropoxide and niobium pentaethoxide in 1,4-butanediol at 300 °C (solvothermal method), and the products were nitrified in an NH₃ flow at 600 °C. The physicochemical property of the thus-obtained N-and Nb-co-doped titanias and visible-light response photocatalytic activity of FeO_x-loaded N-and Nb-co-doped titanias were investigated. The N-and Nb-co-doped titanias had larger absorptions in the visible-light range as compared to the only N-doped titania samples. In ESR spectra of the Nb-modified TiO₂ samples annealed at 300 °C after the nitrification, signals due to Ti³⁺ and oxygen vacancies, which accelerate the recombination of the photo-generated electrons and holes, were clearly observed. On the other hand, for the N-and Nb-co-doped titanias annealed at 500 °C, the signals due to Ti³⁺ and oxygen vacancies decreased significantly. Actually, the FeO_x-loaded N-and Nb-co-doped samples annealed at 500 °C exhibited a higher photocatalytic activity for a photocatalytic decomposition of acetaldehyde under visible-light irradiation.

Abstract: Structural deformation during uniaxial drawing of polyethylene-block-polystyrene (PE-b-PS) copolymer film was analyzed by in-situ small angle X-ray scattering (SAXS) measurement. The PE-b-PS film was prepared by solution casting, followed by isothermally crystallizing from melt. The obtained film exhibits the characteristic bicontinuous crystalline/amorphous morphology. Initial stage of uniaxial drawing induces the orientation of such crystalline/amorphous phases, but these phase separation is destroyed in the latter stage. In contrast, solvent swelling treatment successfully induces the orientation of crystalline/amorphous phases with keeping the phase continuity.