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Full-Text Articles in Physics

Optical Properties And Electronic Structure Of Mgausn, S. J. Lee, J. M. Park, T. A. Wiener, L. L. Miller, David W. Lynch Sep 2001

Optical Properties And Electronic Structure Of Mgausn, S. J. Lee, J. M. Park, T. A. Wiener, L. L. Miller, David W. Lynch

Physics and Astronomy Publications

The optical conductivity spectrum of single-crystal MgAuSn was measured by spectroscopic ellipsometry in the energy range 1.5–5.0 eV. The spectrum has a large peak at 2.9 eV and a small shoulder around 4.3 eV. The band structure, density of states, and interband contribution to the optical conductivity were calculated with the tight-binding linear muffin-tin orbital method in the atomic-sphere approximation. The intraband contribution to the optical conductivity was added using the Drude response fitted to the experimental data. The total theoretical spectrum, including the intraband contribution, agrees well with experimental data.


Structural Characterization Of Thin Film Photonic Crystals, G. Subramania, Rana Biswas, Kristen P. Constant, M. M. Sigalas, Kai-Ming Ho May 2001

Structural Characterization Of Thin Film Photonic Crystals, G. Subramania, Rana Biswas, Kristen P. Constant, M. M. Sigalas, Kai-Ming Ho

Materials Science and Engineering Publications

We quantitatively analyze the structure of thin film inverse-opal photonic crystals composed of ordered arrays of air pores in a background of titania. Ordering of the sphere template and introduction of the titania background were performed simultaneously in the thin film photonic crystals. Nondestructive optical measurements of backfilling with high refractive index liquids, angle-resolved reflectivity, and optical spectroscopy were combined with band-structure calculations. The analysis reveals a thin film photonic crystal structure with a very high filling fraction (92–94 %) of air and a substantial compression along the c axis (∼22–25%).


Optical Properties Of Rni2b2c (R=Y,Tb,Er,Dy), S. J. Lee, B. K. Cho, Paul C. Canfield, David W. Lynch May 2001

Optical Properties Of Rni2b2c (R=Y,Tb,Er,Dy), S. J. Lee, B. K. Cho, Paul C. Canfield, David W. Lynch

Physics and Astronomy Publications

The optical properties of single crystals of RNi2B2C (R=Y,Tb,Er, and Dy) were measured between 1.7 and 5.2 eV at room temperature using a spectroscopic ellipsometer. The spectra for all compounds are similar and the peak positions appear in a similar energy region. The similarity of the spectra of RNi2B2C (R=Tb,Er,Dy) to that of YNi2B2C indicates that the rare-earth 4f states are not actively involved in the optical transitions.


Evolution Of Two-Dimensional Wormlike Nanoclusters On Metal Surfaces, Woei Wu Pai, John F. Wendelken, C. R. Stoldt, Patricia A. Thiel, James W. Evans, Da-Jiang Liu Apr 2001

Evolution Of Two-Dimensional Wormlike Nanoclusters On Metal Surfaces, Woei Wu Pai, John F. Wendelken, C. R. Stoldt, Patricia A. Thiel, James W. Evans, Da-Jiang Liu

Chemistry Publications

A pinch-off phenomenon is discovered in the evolution of 2D wormlike nanoclusters formed in homoepitaxial adlayers. This feature is shown to distinguish mass transport via periphery diffusion from other mechanisms. Continuum modeling of such evolution accurately describes experimental observations, particularly if one incorporates the anisotropy in step-edge line tension.


No Well-Defined Remnant Fermi Surface In Sr2cuo2cl2, S. Haffner, D. P. Brammeier, C. G. Olson, L. L. Miller, David W. Lynch Apr 2001

No Well-Defined Remnant Fermi Surface In Sr2cuo2cl2, S. Haffner, D. P. Brammeier, C. G. Olson, L. L. Miller, David W. Lynch

Physics and Astronomy Publications

In angle-resolved photoelectron spectra of the antiferromagnetic insulators Ca2CuO2Cl2 and Sr2CuO2Cl2, a sharp drop of the spectral intensity of the lowest-lying band is observed along a line in k space equivalent to the Fermi surface of the optimally doped high-temperature superconductors. This was interpreted as a signature of the existence of a remnant Fermi surface in the insulating phase of the high-temperature superconductors. In this paper it is shown that the drop of the spectral intensity is not related to the spectral function but is a consequence of the electron-photon matrix element.


Magnetic Force Microscopy Study Of Magnetization Reversal In Sputtered Fesial(N) Films, Chester C.H. Lo, J. E. Snyder, J. S. Leib, R. Chen, B. Kriegermeier-Sutton, Matthew J. Kramer, David C. Jiles, M. T. Kief Mar 2001

Magnetic Force Microscopy Study Of Magnetization Reversal In Sputtered Fesial(N) Films, Chester C.H. Lo, J. E. Snyder, J. S. Leib, R. Chen, B. Kriegermeier-Sutton, Matthew J. Kramer, David C. Jiles, M. T. Kief

Materials Science and Engineering Publications

The magnetization reversal in a series of rf-sputtered FeSiAl(N) films has been studied using magnetic force microscopy. A system has been developed which has the capability to image domain structure while an in-plane magnetic field is applied in situ. All films exhibited a stripe domain structure in zero applied field which was indicative of a perpendicular component of domain magnetization which alternates in sign. All films showed a similar sequence of magnetization processes: on reducing the applied field from saturation a fine stripe domain structure nucleated and then coarsened as the field was decreased to zero. Local switching of ...


Optical And Magneto-Optical Investigation On Electronic Structure Of Ordered Ferromagnetic Fe3pt, K. J. Kim, S. J. Lee, T. A. Wiener, David W. Lynch Jan 2001

Optical And Magneto-Optical Investigation On Electronic Structure Of Ordered Ferromagnetic Fe3pt, K. J. Kim, S. J. Lee, T. A. Wiener, David W. Lynch

Physics and Astronomy Publications

The optical and magneto-opticalproperties of ordered Fe3Pt have been investigated by spectroscopicellipsometry and magneto-opticalKerrspectroscopy. The diagonal component of the optical conductivity tensor of the compound exhibits a broad absorption peak at about 2 eV, which is shifted by about 0.5 eV to lower energies from the corresponding one in pure bcc Fe. The Kerr angle spectrum of the compound disperses quite similarly in both spectral trend and magnitude to that of pure Fe below 3.5 eV but differently above it. The lower-energy shift of the 2-eV-absorption structure of the compound is interpreted as due to the shift of ...


Fe−3s Core-Level Splitting And Local Magnetism In Fe2val, Ye Feng, M. V. Dobrotvorska, James W. Anderegg, C. G. Olson, David W. Lynch Jan 2001

Fe−3s Core-Level Splitting And Local Magnetism In Fe2val, Ye Feng, M. V. Dobrotvorska, James W. Anderegg, C. G. Olson, David W. Lynch

Physics and Astronomy Publications

X-ray and soft x-ray photoelectron spectra were taken on Fe2VAl samples. The Fe−3s spectra show a shoulder on the higher binding energy side of the main peak, split by ≈4.7 eV. Based on current understanding of core-level multiplet splitting in transition-metal compounds, we believe this is direct evidence of a local moment in Fe2VAl.