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Digitale Medien

Fabrication of transparent iron-oxide films by means of sol-gel synthesis (abstract) (1988)

Yamaguchi, K. ; Fujii, T. ; Kuranouchi, S. ; [weitere]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 64 (1988), S. 5452-5452

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Details

ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Transparent iron-oxide films were fabricated by sol-gel synthesis using a solution of ferric nitrate (III) dissolved in ethylene glycol.1 The solution was kept at 80 °C and stirred constantly in a nitrogen atmosphere. The gel with an appropriate viscosity was spin coated on soft glass plates, then dried and heated in air at various temperatures for 5 h. The films thus prepared are about 0.2 μm thick, amber colored, and especially transparent in the near-infrared region, whose transmittance exceeds 90%. Maximum saturation magnetization 4πMs=0.74 kG [curve (a)] was obtained by annealing at 450 °C, which is still insufficient to use practical application. Reduction heat treatment in a hydrogen atmosphere is found to be very effective to improve magnetic properties: 4πMs is increased to 3 kG [curve (b)], which is about four times as large as the previous one, but the films become semitransparent due to formation of magnetite particles. Original high transmittance recovers by successive annealing in air at 400 °C without any degradation of magnetic properties [curve (c)], where diffraction peaks of maghemite were observed. This strongly suggests that magnetic anisotropy may be arbitrarily controlled by forming linear chains of ferromagnetic particle clusters through reduction heat treatment in a magnetic field. Faraday rotation θF of the samples was also measured. These films are promising as a new type magneto-optic material.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.342345

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Digitale Medien

Extended Hartree-Fock (EHF) theory of chemical reactions (1988)

Yamaguchi, K. ; Takahara, Y. ; Fueno, T. ; [weitere]

Springer

Theoretical chemistry accounts 73 (1988), S. 337-364

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Details

ISSN: 1432-2234

Schlagwort(e): Triplet instability ; Radical character ; Spin projected UMP ; Reaction mechanism ; Transition structures

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie

Notizen: Abstract The triplet-instability analysis of the closed-shell RHF solutions has been carried out in relation to the orbital and spin correlation effects for various transition structures (TS) and reaction intermediates. It is found that the RHF solutions even for cyclic transition states of the Woodward-Hoffmann symmetry-allowed reactions often involve the triplet instability, indicating the crucial role of correlation corrections. The di- and tetra-radical characters for the transition structures are calculated by the projected UHF (PUHF) solutions resulting from the instability. The spin projection is also crucial for the UHF Møller-Plesset (UMP) correlated wavefunctions obtained for the transition structures of 1,3-dipolar, Diels-Alder, ene and related reactions. The relative stability between cyclic and acyclic TS for these reactions is examined at the approximately projected UHF MP2 (APU MP2) level. The former is found to be more favorable than the latter if the correlation correction is taken into account for TS in a well-balanced manner.