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Articles 31711 - 31740 of 36568

Full-Text Articles in Physical Sciences and Mathematics

Magnetic And Magneto-Optical Properties Of MnXPt1–X–YZnY, Kurt W. Wierman, Roger D. Kirby Apr 1996

Magnetic And Magneto-Optical Properties Of MnXPt1–X–YZnY, Kurt W. Wierman, Roger D. Kirby

Roger Kirby Publications

In this work we have prepared thin films of the ternary alloy MnxPt1–x–yZny by magnetron sputtering onto quartz substrates. We have found a wide range of compositions which are strongly ferromagnetic at room temperature. A transition from a cubic to tetragonal phase with decreasing Pt content is confirmed by x-ray diffraction. X-ray diffraction measurements also show a strong (001) reflection consistent with long range order along the c axis for the tetragonal phase. These films show large complex Kerr rotations (up to 0.7°) in the visible spectrum. This combined with their anisotropic structure suggests …

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Spin Polarization Of The Conduction Bands And Secondary Electrons Of Gd(0001), Dongqi Li, J. Pearson, S.D. Bader, D.N. Mcilroy, C. Waldfried, Peter A. Dowben Apr 1996

Spin Polarization Of The Conduction Bands And Secondary Electrons Of Gd(0001), Dongqi Li, J. Pearson, S.D. Bader, D.N. Mcilroy, C. Waldfried, Peter A. Dowben

Peter Dowben Publications

Angle- and spin-resolved photoemission was utilized to investigate the 5d bulk bands and the surface state of Gd(0001) in the temperature range of 130–350 K. The bulk bands at 1–2 eV below the Fermi energy EF show Stoner-like behavior, while the temperature dependence of the surface state near EF indicates spin-mixing behavior due to fluctuating local 5d moments. The secondary electron spectra of the Gd surfaces both before and after initial oxygen adsorption show a polarization dip at low kinetic energies due to the extra scattering channel for minority electrons via the unoccupied 4f level. The temperature dependencies …

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Magnetic Viscosity And Switching Volumes Of Annealed Fe/Pt Multilayers, C.P. Luo, Z.S. Shan, David J. Sellmyer Apr 1996

Magnetic Viscosity And Switching Volumes Of Annealed Fe/Pt Multilayers, C.P. Luo, Z.S. Shan, David J. Sellmyer

David Sellmyer Publications

Magnetic viscosity and the phenomenon of the sweep-rate dependence of the coercivity are important for the characterization of magnetic recording media. The activation volume of magnetization reversal or switching volume is directly related to medium noise. The magnetic viscosity behavior of annealed Fe/Pt multilayers was studied and the switching volumes were obtained by both measurements of the sweep-rate dependence of coercivity and time dependence of magnetization. It is found that samples with larger coercivities have smaller switching volumes, and an estimate of the magnetic grain diameter is about 9 nm. The coercivity mechanisms are also discussed.

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Mössbauer Study Of Permanent-Magnet R2Fe17-XMXCY Compounds, I. A. Al-Omari, E.W. Singleton, Y. Zheng, George C. Hadjipanayis, David J. Sellmyer Apr 1996

Mössbauer Study Of Permanent-Magnet R2Fe17-XMXCY Compounds, I. A. Al-Omari, E.W. Singleton, Y. Zheng, George C. Hadjipanayis, David J. Sellmyer

David Sellmyer Publications

We report Fe57 Mössbauer spectroscopy studies of the effect of carbon doping on the magnetic properties of the Fe sites of R2Fe17-xMxCy, and of the presence of multiple phases in these systems. In this study two systems, Sm2Fe14Al3Cy, where y=0, 1.0, 2.0, and 3.0, and Nd2Fe14.54Si2.46Cy, where y=0, 0.432, and 2.544, were measured at room temperature and analyzed. The ternary compounds R2Fe17-xMxCy studied here have the …

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Co-Sm (1̅100)[0001]//Cr (1̅21̅)[ 1̅01] Epitaxy And Its Effects On Magnetic Properties Of Co-Sm//Cr Films, Yi Liu, David J. Sellmyer, B. W. Robertson Apr 1996

Co-Sm (1̅100)[0001]//Cr (1̅21̅)[ 1̅01] Epitaxy And Its Effects On Magnetic Properties Of Co-Sm//Cr Films, Yi Liu, David J. Sellmyer, B. W. Robertson

David Sellmyer Publications

It is well known that the Cr underlayer plays a critical role in generating large in-plane coercivity in Co-based magnetic thin films. In this paper we report in detail the Co-Sm (1̅100)[0001]//Cr (1̅21̅)[ 1̅01] epitaxy revealed by high resolution electron microscopy. The lattice mismatch between Co-Sm (1̅100) and Cr (1̅21̅) is less than 2%, suggesting an energetically favorable configuration. The high anisotropy observed in Co-Sm films is discussed by this epitaxial relation.

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Self-Stabilized Magnetic Colloids: Ultrafine Co Particles In Polymers, Diandra Leslie-Pelecky, X.Q. Zhang, Reuben D. Reike Apr 1996

Self-Stabilized Magnetic Colloids: Ultrafine Co Particles In Polymers, Diandra Leslie-Pelecky, X.Q. Zhang, Reuben D. Reike

Diandra Leslie-Pelecky Publications

Self-stabilized magnetic colloids consist of magnetic particles dispersed in an appropriate matrix. Fixing the particles in a stabilizing matrix has the advantage of preventing particle agglomeration, increasing resistance to oxidation, and allowing control over the interparticle spacing and particle size. We describe the chemical synthesis of cobalt nanoparticles in a polystyrene/triphenylphosphine polymer matrix. Depending on the synthesis parameters, magnetic properties of the as-synthesized nanocomposites range from superparamagnetic to ferromagnetic with coercivities on the order of 130 Oe. Solvent choice and polymer crosslinking significantly affect the magnetic properties. Annealing in vacuum produces coercivities of up to 600 Oe and remanence ratios …

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Superparamagnetic Magnetic Force Microscopy Tips, P.F. Hopkins, John Moreland, S.S. Malhotra, Sy_Hwang Liou Apr 1996

Superparamagnetic Magnetic Force Microscopy Tips, P.F. Hopkins, John Moreland, S.S. Malhotra, Sy_Hwang Liou

Sy-Hwang Liou Publications

We report on magnetic force microscopy (MFM) images of a thin-film magnetic recording head taken using batch micromachined silicon tips coated with nanocomposite Fe60 (SiO2)40 and Fe70 (SiO2)30 films. The small Fe grain size (<10 nm) and dilute Fe volume fraction (0.29–0.4) of these granular films produce tip coatings of low remanence and essentially zero coercivity, reduced by the superparamagnetic properties of these films. We have used these tips to obtain MFM images of the write field of the head with high spatial and magnetic-field resolution. In comparison to images taken using commercial Co85Cr15-coated tips, these MFM images show reduced tip memory effects and clearly delineate the gap field from the pole pieces.

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Magnetic Properties Of Nanometer-Size Copt Particles, Sy_Hwang Liou, Yi Liu, S.S. Malhotra, M. Yu, David J. Sellmyer Apr 1996

Magnetic Properties Of Nanometer-Size Copt Particles, Sy_Hwang Liou, Yi Liu, S.S. Malhotra, M. Yu, David J. Sellmyer

Sy-Hwang Liou Publications

We have prepared nanometer-size, isolated CoPt particles. The particles in the range of 100–300 nm in diameter were formed by annealing thin films in the temperature range of 550–800 °C. Films with magnetic coercivity as high as 30 kOe were achieved. The results indicate that the high magnetic coercivity was obtained because the crystallite size approaches that of noninteracting single-domain particles.

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High Coercivity Rare Earth–Cobalt Films, S.S. Malhotra, Yi Liu, Z.S. Shan, Sy_Hwang Liou, D.C. Stafford, David J. Sellmyer Apr 1996

High Coercivity Rare Earth–Cobalt Films, S.S. Malhotra, Yi Liu, Z.S. Shan, Sy_Hwang Liou, D.C. Stafford, David J. Sellmyer

Sy-Hwang Liou Publications

Rare earth–cobalt (RCo, R=Sm, Pr) films with thicknesses from 30 to 700 nm have been prepared with and without a Cr underlayer by dc magnetron sputtering from a R2Co7 composite target. The as-deposited SmCo films with a Cr underlayer (SmCo║Cr) have magnetic coercivities of about 500–2800 Oe and the PrCo║Cr films have coercivities of about 100–300 Oe, but after annealing at 500 °C coercivities as high as 31 kOe for SmCo║Cr films and 10 kOe for PrCo║Cr films were observed. The as-deposited PrCo films are composed mostly of an amorphous phase with about 30 vol % of …

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Site Affinity Of Substituents In Nd₂Fe₁₇₋ₓtₓ (T=Cu,Zr,Nb,Ti,V) Alloys, William B. Yelon, Z. Hu, William Joseph James, G. K. Marasinghe Apr 1996

Site Affinity Of Substituents In Nd₂Fe₁₇₋ₓtₓ (T=Cu,Zr,Nb,Ti,V) Alloys, William B. Yelon, Z. Hu, William Joseph James, G. K. Marasinghe

Physics Faculty Research & Creative Works

In order to understand the magnetic properties of the substituted rare-earth-iron alloys, it is especially important to know the location of the substitutional atoms within the iron lattice. The site distributions of some nontransition-metal substituents in the substituted Nd2Fe17-xTx alloys have previously been reported. Here we report the site distributions of some transition-metal substituents (Cu,Zr,Nb,Ti,V) in the Nd2Fe17-xTx alloys and compare them with those of the nontransition-metal substituted compounds. Rietveld analysis of neutron powder diffraction data indicates that the nontransition-metal substituents show very similar site affinity at low substituent content. …

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Neutron Diffraction And Magnetic Studies Of Rfe₁₂₋ₓtₓcY (R=Y,Er; T=V,Ti,Mo) Alloys, Z. Hu, William B. Yelon, X. D. Zhang, William Joseph James Apr 1996

Neutron Diffraction And Magnetic Studies Of Rfe₁₂₋ₓtₓcY (R=Y,Er; T=V,Ti,Mo) Alloys, Z. Hu, William B. Yelon, X. D. Zhang, William Joseph James

Physics Faculty Research & Creative Works

RFe12-xTxCy, (R=Y,Er; T=V,Ti,Mo) alloys were prepared by rf induction melting and analyzed using neutron powder diffraction and superconducting quantum interference device (SQUID) measurements. Rietveld analysis of the neutron diffraction data indicates that V, Ti, and Mo atoms all prefer the 8i sites. The refined amount of carbon atoms found in the interstitial sites from neutron diffraction data is significantly less than the nominal carbon content. All samples have the easy direction along the c axis. The Er sublattice couples to the Fe sublattice antiferromagnetically. The average Fe site moments range from 1.3 to 2.8 …

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Neutron Diffraction Studies Of Ndₙfeₘ₋ₓ₋YVₓalY [(N,M)=(1,12), (2,17), (3,29)], Z. Hu, William B. Yelon, William Joseph James Apr 1996

Neutron Diffraction Studies Of Ndₙfeₘ₋ₓ₋YVₓalY [(N,M)=(1,12), (2,17), (3,29)], Z. Hu, William B. Yelon, William Joseph James

Physics Faculty Research & Creative Works

Several NdnFem-x-yVxAly [(n,m)=(1,12), (2,17), (3,29)] samples were prepared and analyzed using neutron powder diffraction. Rietveld analysis of the neutron diffraction data indicates that the V and Al substituents take those sites with similar environments in all three phases, as observed in our previous study of Ti-substituted compounds. It was confirmed that the diffraction data of the 3:29 compound can be better refined using the A2/m space group than using the P21/c space group. The SQUID measurements show that all samples have Curie temperatures well above room temperature. The neutron diffraction results …

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Three-Body Collision Dynamics For Single Ionization Of Helium By Protons And Antiprotons, C. J. Wood, Ronald E. Olson Apr 1996

Three-Body Collision Dynamics For Single Ionization Of Helium By Protons And Antiprotons, C. J. Wood, Ronald E. Olson

Physics Faculty Research & Creative Works

All momentum components of the three outgoing particles are calculated for 100 keV p and p- + He single-ionization collisions. Differential ejected electron cross sections are evaluated for a fixed collision plane defined by the incident momentum vector of the projectile and the final momentum vector of the He+ recoil ion. For proton impact the electron spectra display saddle-point ionization when the transverse recoil ion momentum is small, whereas the electrons are ejected in the backward direction for large transverse recoil ion momenta. The antiproton collisions primarily show backward ejected electrons. However, for the antiproton system there is a decided …

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Oxygen Induced Suppression Of The Surface Magnetization Of Gd(0001), D.N. Mcilroy, C. Waldfried, Dongqi Li, J. Pearson, S.D. Bader, D.-J. Huang, P.D. Johnson, R.F. Sabiryanov, Sitaram Jaswal, Peter A. Dowben Apr 1996

Oxygen Induced Suppression Of The Surface Magnetization Of Gd(0001), D.N. Mcilroy, C. Waldfried, Dongqi Li, J. Pearson, S.D. Bader, D.-J. Huang, P.D. Johnson, R.F. Sabiryanov, Sitaram Jaswal, Peter A. Dowben

Peter Dowben Publications

The effects of oxygen adsorption on the surface magnetization of Gd(0001) have been determined by measuring the polarization of the Gd 4f core levels and the oxygen induced states with spin-resolved photoemission. Calculations of the partial density of states of O/Gd(0001) using the LMTO-ASA method support the photoemission measurements, which indicate that oxidation occurs at low coverages. The loss of surface magnetic order with oxygen exposure is explained in terms of decreasing indirect coupling.

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Droplet Evaporation And Deformations In An Amplitude Modulated Ultrasonic Field, Nihad E. Daidzic, Rene Stadler, Adrian Melling Apr 1996

Droplet Evaporation And Deformations In An Amplitude Modulated Ultrasonic Field, Nihad E. Daidzic, Rene Stadler, Adrian Melling

Aviation Department Publications

The aim of the report presented is the measurements of droplet oscillations.

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The Physics Of Motocross, Jeffrey R. Giles, Charles D. Ross Apr 1996

The Physics Of Motocross, Jeffrey R. Giles, Charles D. Ross

Chemistry & Physics Faculty Publications

The article describes how the laws of physics allow the motocross rider to control the flight of a motorcycle.

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Auger Resonant Raman Spectroscopy Used To Study The Angular Distributions Of The Xe 4d5/2 → 6p Decay Spectrum, B. Langer, N. Berrah, A. Farhat, Oliver Hemmers, J. Bozek Apr 1996

Auger Resonant Raman Spectroscopy Used To Study The Angular Distributions Of The Xe 4d5/2 → 6p Decay Spectrum, B. Langer, N. Berrah, A. Farhat, Oliver Hemmers, J. Bozek

Environmental Studies Faculty Publications

The Auger resonant Raman effect can be used as a method to eliminate natural lifetime broadening in resonant Auger spectra. We have coupled this method with high-resolution photons from the Advanced Light Source to study angular distributions and decay rates of the Xe4d5/2→6p resonant Auger lines. The angular distribution parameters β of almost all possible final ionic 5p4(3P, 1D, 1S)6p states have been determined. Our data, which remove the discrepancy between previous lower-resolution experimental results, are compared to different theoretical results.

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Oscillatory Doubly Diffusive Convection In A Finite Container, Adam S. Landsberg, Edgar Knobloch Apr 1996

Oscillatory Doubly Diffusive Convection In A Finite Container, Adam S. Landsberg, Edgar Knobloch

WM Keck Science Faculty Papers

Oscillatory doubly diffusive convection in a large aspect ratio Hele-Shaw cell is considered. The partial differential equations are reduced via center-unstable manifold reduction to the normal form equations describing the interaction of even and odd parity standing waves near onset. These equations take the form of the equations for a Hopf bifurcation with approximate D4 symmetry, verifying the conclusions of the preceding paper [A.S. Landsberg and E. Knobloch, Phys. Rev. E 53, 3579 (1996)]. In particular, the amplitude equations differ in the limit of large aspect ratios from the usual Ginzburg-Landau description in having additional nonlinear terms with O(1) coefficients. …

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Oscillatory Bifurcation With Broken Translation Symmetry, Adam S. Landsberg, Edgar Knobloch Apr 1996

Oscillatory Bifurcation With Broken Translation Symmetry, Adam S. Landsberg, Edgar Knobloch

WM Keck Science Faculty Papers

The effect of distant endwalls on the bifurcation to traveling waves is considered. Previous approaches have treated the problem by assuming that it is a weak perturbation of the translation invariant problem. When the problem is formulated instead in a finite box of length L and the limit L--> [infinity] is taken, one obtains amplitude equations that differ from the usual Ginzburg-Landau description by the presence of an additional nonlinear term. This formulation leads to a description in terms of the amplitudes of the primary box modes, which are odd and even parity standing waves. For large L, the equations …

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Stability Analysis Of A Model For The Defect Structure Of Yba2cu3ox, Gregory Kozlowski, Tom Svobodny Apr 1996

Stability Analysis Of A Model For The Defect Structure Of Yba2cu3ox, Gregory Kozlowski, Tom Svobodny

Physics Faculty Publications

Unusual microstructures of YBa2Cu3Ox (123) crystals have been observed. These structures have been shown to pass very high transport currents. A model of the solidification of 123 from a melt with Y2BaCuO5 (211) inclusions indicates that the stability of the 123 interface can depend on the sizes of the 211 inclusions. The observed formations are interpreted in the light of this instability.

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Electron Impact Vibrational Excitation Cross Sections Of Sif4, R. Nagpal, A. Garscadden, Jerry D. Clark Apr 1996

Electron Impact Vibrational Excitation Cross Sections Of Sif4, R. Nagpal, A. Garscadden, Jerry D. Clark

Physics Faculty Publications

Electron drift velocities in mixtures of SiF4 and Ar have been measured using a pulsed‐Townsend type drift tube. A set of vibrational excitation cross sections of electron scattering in SiF4 has been subsequently determined by the swarm analyses of measured transport data in highly dilute SiF4−Ar mixtures. The derived cross sections are consistent with the electron transport properties over an order of magnitude in SiF4 concentration in gas mixtures, thus providing evidence that the main features of their near threshold behavior, and of their absolute magnitude have been captured.

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Fine-Structure Effect For (E,2e) Collisions, Don H. Madison, V. D. Kravtsov, Stephenie J. Jones, Robert P. Mceachran Apr 1996

Fine-Structure Effect For (E,2e) Collisions, Don H. Madison, V. D. Kravtsov, Stephenie J. Jones, Robert P. Mceachran

Physics Faculty Research & Creative Works

For the case of inelastic electron-atom scattering, it has been known for some time that significant spin effects may be observed even if spin-dependent forces on the projectile can be ignored. These spin effects result from the Pauli principle and this phenomenon has become known as the fine-structure effect. Recently, the question of whether or not these same types of effects should be observed for atomic ionization has been considered and the initial indications are that significant spin asymmetries can also be expected for atomic ionization if the final ion satisfies LS coupling and the final J state of the …

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Atomic Data For Astrophysics. I. Radiative Recombination Rates For H-Like, He-Like, Li-Like, And Na-Like Ions Over A Broad Range Of Temperature, D. A. Verner, Gary J. Ferland Apr 1996

Atomic Data For Astrophysics. I. Radiative Recombination Rates For H-Like, He-Like, Li-Like, And Na-Like Ions Over A Broad Range Of Temperature, D. A. Verner, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present new calculations and analytic fits to the rates of radiative recombination towards H-like, He-like, Li-like and Na-like ions of all elements from H through Zn (Z=30). The fits are valid over a wide range of temperature, from 3 K to 109 K.

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High Order Harmonic Generation In Atom Clusters, Thomas D. Donnelly, T. Ditmire, K. Neuman, M. D. Perry, R. W. Falcone Apr 1996

High Order Harmonic Generation In Atom Clusters, Thomas D. Donnelly, T. Ditmire, K. Neuman, M. D. Perry, R. W. Falcone

All HMC Faculty Publications and Research

We report the generation of short-wavelength, high-order harmonics of intense laser radiation from atom clusters. Clusters containing about 103 atoms are produced in a high-pressure gas jet. We show them to be a unique nonlinear medium. Compared with monomer gases they yield a higher appearance intensity for a given harmonic order, stronger nonlinear dependence of harmonic signal on laser intensity, higher-order harmonics, and reduced saturation of the harmonic signal at high laser intensity.

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Effects Of Coherent Coupling Of Autoionizing States On Multiphoton Ionization, N. E. Karapanagioti, D. Charalambidis, Cornelis J. Uiterwaal, C. Fotakis, H. Bachau, I. Sanchez, E. Cormier Apr 1996

Effects Of Coherent Coupling Of Autoionizing States On Multiphoton Ionization, N. E. Karapanagioti, D. Charalambidis, Cornelis J. Uiterwaal, C. Fotakis, H. Bachau, I. Sanchez, E. Cormier

C.J.G.J. Uiterwaal Publications

We present the experimental and theoretical investigation of the effects of the strong electromagnetic coupling of two autoionizing states (AIS’s) on the photoionization properties of an atomic system. These effects are observed by probing the ladder system from the ground state of the atom through a weak two-photon transition to the region of the lower AIS. The experimental observation of the modification of the total ionization and partial photoelectron spectra at different wavelengths of the coupling and probe lasers are accurately reproduced by a theoretical analysis which uses a density-matrix approach. Both theory and experiment indicate a strong inhibition of …

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An Electroabsorption Study Of Porous Silicon, Melanie Fewings Apr 1996

An Electroabsorption Study Of Porous Silicon, Melanie Fewings

WWU Honors College Senior Projects

Bulk silicon is an indirect band gap material. When carriers are injected into bulk silicon, electron-hole recombination takes place thermally via phonon exchange, and not by emission of photons. Porous silicon, on the other hand, is a fairly efficient emitter of light in the visible region. Much research is currently under way to find out what makes porous silicon able to emit light. One main theory suggests that the energy bands of bulk silicon may be "squeezed" by being quantum confined, and porous silicon is just an array of quantum silicon wires. Another possibility is that defects in the huge …

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Critical Behavior Of A Quantum Spherical Model In A Random Field, Thomas Vojta, Michael Schreiber Apr 1996

Critical Behavior Of A Quantum Spherical Model In A Random Field, Thomas Vojta, Michael Schreiber

Physics Faculty Research & Creative Works

We consider the influence of a quenched random field on the critical behavior of a quantum spherical model at the zero-temperature quantum phase transition. We find a complete solution of the model for arbitrary translationally invariant pair interactions. It turns out that the critical behavior for zero as well as finite temperatures is dominated by static random field fluctuations rather than by quantum or thermal fluctuations. Therefore the critical behavior close to the zero-temperature quantum phase transition is identical to that close to a finite-temperature transition. The system does not show a crossover from quantum to classical behavior.

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Ionization Of Rydberg Wave Packets By Subpicosecond, Half-Cycle Electromagnetic Pulses, C. Raman, C. W. S. Conover, C. I. Sukenik, P. H. Bucksbaum Apr 1996

Ionization Of Rydberg Wave Packets By Subpicosecond, Half-Cycle Electromagnetic Pulses, C. Raman, C. W. S. Conover, C. I. Sukenik, P. H. Bucksbaum

Physics Faculty Publications

We have studied the ionization of Rydberg wave packets by subpicosecond, nearly unipolar electromagnetic field pulses, in the regime where the duration of the electric field is less than the classical Kepler orbit time 2n3 for the wave packet. In contrast to the subpicosecond optical pulses, subpicosecond field pulses can ionize wave packets when the probability density near the inner turning point of the Kepler orbit is low. The transfer of energy from the electromagnetic field to essentially free electrons demonstrates that the pulses are substantially shorter than one field cycle. Such half-cycle pulses can track the wave packet throughout …

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Neutron Diffraction And Mössbauer Spectral Study Of The Nd₂Fe₁₆Ticₓ Solid Solutions, Gaya Kanishka Marasinghe, Peter C. Ezekwenna, William Joseph James, Gary J. Long, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, Fernande Grandjean Apr 1996

Neutron Diffraction And Mössbauer Spectral Study Of The Nd₂Fe₁₆Ticₓ Solid Solutions, Gaya Kanishka Marasinghe, Peter C. Ezekwenna, William Joseph James, Gary J. Long, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, Fernande Grandjean

Chemistry Faculty Research & Creative Works

Three samples of , with x equal to 0.0, 0.3, and 2.8, with the Th2Zn17-type rhombohedral structure, have been studied by powder x-ray and neutron diffraction, magnetic measurements, and Mössbauer spectroscopy. Nd2Fe16Ti and Nd2Fe16TiC0.3 were synthesized by induction melting stoichiometric amounts of the constituent elements, whereas Nd2Fe16TiC2.8 was synthesized by methane-derived gas phase insertion of carbon into finely ground Nd2Fe16Ti at 600 K. The neutron diffraction determined titanium site occupancies are similar in both Nd2Fe16 …

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Frequency Response Enhancement Of A Flow Sensor Using Diamond Thin Films Synthesized By Plasma Cvd, John Curren Hagwood Apr 1996

Frequency Response Enhancement Of A Flow Sensor Using Diamond Thin Films Synthesized By Plasma Cvd, John Curren Hagwood

Electrical & Computer Engineering Theses & Dissertations

Theoretical modeling conducted previously in our Microelectronics Laboratory has shown that a layer of diamond film inserted between a metal film and a substrate will enhance the frequency response of a conventional thin film flow sensor. This thesis involved fabricating and testing a conventional thin film sensor of nickel on quartz (Ni/Q) and a diamond enhanced sensor (Ni/D/Q) for comparative frequency response analysis to validate the theory. Diamond films were grown onto quartz substrates using a microwave plasma enhanced chemical vapor deposition process. Conditions were established to synthesize continuous diamond films on quartz substrates. These films were characterized by scanning …

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