Advanced Micro-Device Engineering III

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Authors: Masahiro Naito, Kenta Hiiragi, Ayako Sato, Hiroshi Maruyama, Masahisa Ito
Abstract: We have performed X-ray magnetic diffraction experiments of a ferromagnetic binary alloy Fe3Pt in order phase, and have measured separately spin and orbital magnetic form factors. By a curve-fitting analysis in which atomic-model form factors of Fe-3d and Pt-5d electrons under the dipole approximation are assumed, we have obtained the spin and orbital magnetic moments of Fe and Pt atoms separately. The present result is comparable to those of other experimental and theoretical studies, which shows the validity of this experimental method.
Authors: Naoto Go, Kosuke Suzuki, Shun Emoto, Masayoshi Itou, Yoshiharu Sakurai, Hiroshi Sakurai
Abstract: The effects of strain and interface roughness at the Co/Pd interface are investigated from the viewpoint of perpendicular magnetic anisotropy (PMA) using the DV-Xα cluster model calculation method. It is found that spin projected occupation number ratio of magnetic quantum number |m| = 2 for the Co 3d electrons enhances by expanding the lattice within a close-packed plane of fcc stacking and, hence, enhances the PMA. Rough interface decreases the spin projected occupation number ratio of |m| = 2 and, hence, decreases the PMA. These results explain the PMA properties of Co/Pd multilayers fabricated using molecular beam epitaxy (MBE) technique and RF sputtering techniques.
Authors: Kohjiro Kobayashi, Kosuke Suzuki, Hiroshi Sakurai
Abstract: sotropic and directional autocorrelation functions are calculated for 14 electron diatomic molecules, N2, CO, and BF, using the DV-Xα method. In order to investigate the effect of chemical bonds for the molecules, directional autocorrelation functions parallel and perpendicular to the bond are investigated. The anisotropies of the directional autocorrelation functions of N2 and CO are different from the anisotropy of BF, which has a wave shape.
Authors: Kohjiro Kobayashi, Kosuke Suzuki, Hiroshi Sakurai
Abstract: sotropic and directional autocorrelation functions have been calculated using the DV-Xα method on polyethylene type clusters to investigate the effect of its characteristic dimensionality of the wavefunctions. Directional autocorrelation functions are calculated along the c-axis, the direction of the long chain of carbon atoms, and along an axis perpendicular to it. The analysis of the molecular orbital dependence of the autocorrelation function reveals that the long range order along the c-axis can be enhanced as increasing the length of the cluster and the orbitals near the highest occupied molecular orbital have a key role for the one-dimensional order.
Authors: Kazushi Hoshi, Hiroki Kato, Takayuki Fukunaga, Shinichi Furusawa, Hiroshi Sakurai
Abstract: Mn1-xZnxFe2O4 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) are synthesized using sintering coprecipitation method. The coprecipitation retains from 0 hours to 48 hours at 1200 °C. The synthesis of a Mn0.6Zn0.4Fe2O4 is almost completed even though retaining time is for 0 hours at 1200 °C. The crystal growth of Mn0.6Zn0.4Fe2O4 particles proceeds rapidly retaining up to 6 hours and saturates retaining more than 6 hours at 1200 °C. The permeability and the electric resistivity are affected by the crystal growth of Mn0.6Zn0.4Fe2O4 particles.
Authors: Kazushi Hoshi, Haruki Kenmochi, Takayuki Fukunaga, Shinichi Furusawa, Hiroshi Sakurai
Abstract: Mn0.7Zn0.3Fe2O4 is synthesized by sintering the nanosize precursor with sintering aids, which is synthesized by the coprecipitation method. The crystal growth of Mn0.7Zn0.3Fe2O4 is controlled by the amount of sintering aids. Complex permeability is explained by the Maxwell-Garnett (MG) effective medium model. The ferromagnetic resonance frequency more than 1 GHz can be explained by the shape anisotropy under the sintering process of the Mn0.7Zn0.3Fe2O4 particles. These results suggest possibility of Mn0.7Zn0.3Fe2O4 as a high frequency device material.
Authors: Shinichi Furusawa, Yuusuke Koyama
Abstract: Li2xZn2-3xTi1+xO4 (x=0.33, 0.50, 0.60) crystals were grown in a double-mirror type optical floating-zone furnace. The electrical conductivity of Li2xZn2-3xTi1+xO4 of crystal was measured in a frequency range from 100 Hz to 10 MHz and in a temperature range from 330 to 700 K, in nitrogen gas. It was revealed the electrical conductivity mechanism changes at the temperature region of 480520 K. The electrical conductivity of polycrystalline Li2xZn2-3xTi1+xO4 (x=0.6) shows nearly two orders of magnitude higher values compared to other samples.
Authors: Kenji Kaneda, Tamihiro Gotoh
Abstract: Electrical properties in dc-sputtered amorphous InGaZnO4 films have been investigated using the thermopower and resistivity measurements. The amorphous InGaZnO4 films show n-type conduction at room temperature, and electrical activation energy of ~0.47 eV. The resistivity and Seebeck coefficient at room temperature were ~2×104 Ωm and 1.5 mV/K for as-deposited sample. The resistivity and Seebeck coefficient decreased to ~2×100 Ω·m and 2.7 mV/K when the sample was annealed at 670770 K. Slow response of photocurrent was also observed. Partial crystallization and structural change cause the improvement of electron transport with annealing treatments.
Authors: Kenji Kakiage, Shiho Ishiuchi, Tôru Kyômen, Minoru Hanaya
Abstract: Transparent thin films of strontium titanate (SrTiO3) were formed on the substrate of quartz glass plate by RF magnetron sputtering with changing the substrate temperatures during the sputtering from 100 to 700 °C. The particle size and the lattice constant of the cubic-SrTiO3 crystallites composing the film were exhibited to be changed from 13 to 48 nm and from 4.02 to 3.96 Å, respectively, by the change of the substrate temperatures from 400 to 700 °C. The UV absorption edges of the transparent film samples shifted to longer wavelength with the increase of the particle size and the decrease of the lattice constant of the nanocrystalline SrTiO3.

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