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Full-Text Articles in Physics

Optical And Magneto-Optical Properties And Electronic Structures Of Single-Crystalline Ral2 (R=Y, La, Ce, Pr, And Lu), R. J. Lange, S. J. Lee, K. J. Kim, Paul C. Canfield, David W. Lynch Dec 2000

Optical And Magneto-Optical Properties And Electronic Structures Of Single-Crystalline Ral2 (R=Y, La, Ce, Pr, And Lu), R. J. Lange, S. J. Lee, K. J. Kim, Paul C. Canfield, David W. Lynch

Physics and Astronomy Publications

The diagonal optical conductivity spectra of single crystals of RAl2 (R=Y, La, Ce, Pr, and Lu) were measured at room temperature by spectroscopic ellipsometry in the 1.5–5.6−eV range. All the compounds exhibit two strong interband absorption peaks at about 1.8 and 3.6 eV for YAl2 and LuAl2, and at about 2.0 and 3.0 eV for LaAl2, CeAl2, and PrAl2. Such differences in the second peak position appear in the theoretical optical conductivity spectra calculated from their band structures obtained by the tight-binding linear-muffin-tin-orbitals method. Most of the contributions to the two ...


Electronic Structure Of Quasicrystalline Surfaces: Effects Of Surface Preparation And Bulk Structure, V. Fournée, P. J. Pinhero, J. W. Anderegg, Thomas A. Lograsso, A. R. Ross, Paul C. Canfield, I. R. Fisher, Patricia A. Thiel Dec 2000

Electronic Structure Of Quasicrystalline Surfaces: Effects Of Surface Preparation And Bulk Structure, V. Fournée, P. J. Pinhero, J. W. Anderegg, Thomas A. Lograsso, A. R. Ross, Paul C. Canfield, I. R. Fisher, Patricia A. Thiel

Chemistry Publications

We elucidate the nature of the surface electronic properties of quasicrystalline Al-Pd-Mn. We do this by using photoelectron and Auger electron spectroscopies, and by making a variety of comparisons—across types of bulk samples, and across methods of surface preparation. The main conclusions are these: (i) The narrow Mn 2p3/2core-level line observed in the icosahedral phase is a fingerprint of a suppression in the density of states (a pseudogap) at the Fermi level and is not unique to the quasicrystalline phase. It is also independent of the symmetry of the quasicrystalline surface. The Auger line shape is ...


Observation Of A Metamagnetic Phase Transition In An Itinerant 4f System Via The Magneto-Optic Kerr Effect: Ce(Fe1−Xcox)2, R. J. Lange, I. R. Fisher, Paul C. Canfield, Vladimir P. Antropov, S. J. Lee, Bruce N. Harmon, David W. Lynch Sep 2000

Observation Of A Metamagnetic Phase Transition In An Itinerant 4f System Via The Magneto-Optic Kerr Effect: Ce(Fe1−Xcox)2, R. J. Lange, I. R. Fisher, Paul C. Canfield, Vladimir P. Antropov, S. J. Lee, Bruce N. Harmon, David W. Lynch

Physics and Astronomy Publications

The optical and magneto-optical properties of single crystals of YFe2, CeFe2, and Ce(Fe1−xCox)2 (x≃0.1) were measured between 1.4 and 5.0 eV using a rotating-analyzer ellipsometer and a normal-incidence polar Kerr spectrometer. The electronic structures and optical properties of YFe2 and CeFe2 were calculated using the tight-binding linear muffin-tin orbital method in the atomic-sphere approximation. For YFe2 the calculations reproduce the experimental spectra. Alloying CeFe2 with small amounts of Co leads to an electronic instability which is evidenced by a low-temperature antiferromagnetic (AF) phase. The Kerr effect was measured in the AF and field-induced ...


Evidence For A Strong Impact Of The Electron-Photon Matrix Element On Angle-Resolved Photoelectron Spectra Of Layered Cuprate Compounds, S. Haffner, C. G. Olson, L. L. Miller, David W. Lynch Jun 2000

Evidence For A Strong Impact Of The Electron-Photon Matrix Element On Angle-Resolved Photoelectron Spectra Of Layered Cuprate Compounds, S. Haffner, C. G. Olson, L. L. Miller, David W. Lynch

Physics and Astronomy Publications

Little is known about the impact of the electron-photon matrix element on angle-resolved photoelectron spectra of layered cuprate compounds. Using the example of the model layered cuprate Sr2CuO2Cl2, we demonstrate that the electron-photon matrix element has a significant influence on energy distribution curves, rendering their interpretation as images of the spectral function nontrivial.


Temperature Dependence Of The Magnetomechanical Effect In Metal-Bonded Cobalt Ferrite Composites Under Torsional Strain, Y. Chen, John E. Snyder, Kevin W. Dennis, R. William Mccallum, David C. Jiles May 2000

Temperature Dependence Of The Magnetomechanical Effect In Metal-Bonded Cobalt Ferrite Composites Under Torsional Strain, Y. Chen, John E. Snyder, Kevin W. Dennis, R. William Mccallum, David C. Jiles

Materials Science and Engineering Publications

Metal-bonded cobaltferrite composites are promising candidates for torquesensors and other magnetostrictive sensing and actuating applications. In the present study, the temperature dependence of the magnetomechanical effect in a ring-shape cobaltferrite composite under torsional strain has been investigated in the temperature range of −37 to 90 °C. The changes of external axial magnetic field were measured as a function of applied torque. Magnetomechanical sensitivity of ΔHext/Δτ=65 A N−1 m−2 was observed with a magnetomechanical hysteresis of Δτ=±0.62 N m at room temperature (22 °C). These were then measured as a function of temperature. Both decreased ...


Optical Properties And Electronic Structure Of Single Crystals Of Lual2 And Ybal2, S. J. Lee, S. Y. Hong, I. R. Fisher, Paul C. Canfield, Bruce N. Harmon, David W. Lynch Apr 2000

Optical Properties And Electronic Structure Of Single Crystals Of Lual2 And Ybal2, S. J. Lee, S. Y. Hong, I. R. Fisher, Paul C. Canfield, Bruce N. Harmon, David W. Lynch

Physics and Astronomy Publications

The optical conductivities of single crystals of LuAl2 and YbAl2 were measured by spectroscopic ellipsometry in the energy range of 1.4–5.5eV for LuAl2 and 1.4–5.2eV for YbAl2. The optical conductivity spectra of LuAl2 and YbAl2 show similar features except for a difference in magnitude. Both have peaks near 1.8–2.1eV and broad shoulders between 3.0 and 4.0eV. The shoulder is weaker in YbAl2. The band structure, density of states, and optical conductivity were calculated with the tight-binding linear muffin-tin orbital method in the atomic sphere approximation. The calculated optical conductivity ...


Optical And Magneto-Optical Properties Of Rfe2 (R=Gd,Tb,Ho,Lu) And Gdco2, S. J. Lee, R. J. Lange, Paul C. Canfield, Bruce N. Harmon, David W. Lynch Apr 2000

Optical And Magneto-Optical Properties Of Rfe2 (R=Gd,Tb,Ho,Lu) And Gdco2, S. J. Lee, R. J. Lange, Paul C. Canfield, Bruce N. Harmon, David W. Lynch

Physics and Astronomy Publications

The conductivity tensors of single crystals and polycrystals of RFe2 (R=Gd,Tb,Ho,Lu) and GdCo2 were determined in the visible and near UV ranges. The magneto-optical Kerr effect (MOKE) was studied at different temperatures and magnetic fields. The single-crystal data show more features and larger magnitudes in the MOKE spectrum than the polycrystalline data under the same experimental conditions. The theoretical optical conductivity tensors for these compounds were calculated using the tight-binding linear-muffin-tin orbital (TB-LMTO) method in the local spin-density approximation. The agreement between theory and experiment was poor except for LuFe2, in which the 4f shell is ...