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Physics

University of Nebraska - Lincoln

1994

Articles 1 - 30 of 56

Full-Text Articles in Physical Sciences and Mathematics

Energy Spread And Ion Current Measurements Of Several Ion Sources, A. D. Gaus, W. T. Htwe, J. A. Brand, Timothy J. Gay, M. Schulz Dec 1994

Energy Spread And Ion Current Measurements Of Several Ion Sources, A. D. Gaus, W. T. Htwe, J. A. Brand, Timothy J. Gay, M. Schulz

Timothy J. Gay Publications

Energy spread and extracted current measurements are presented for five different types of ion sources: hot cathode, cold cathode, magnetron, microwave, and electron cyclotron resonance (ECR). The measurements were performed with a 45° parallel-plate energy analyzer with a resolution of better than 0.5 eV at 500 eV incident energy. Energy spreads ranged from 0.5 to 4 eV, while total extracted beam currents ranged from 2 to 30 μA. Beam currents due specifically to protons, 3He++ ions, and H+2 ions are also presented. The ECR and magnetron sources gave the best overall performance. These, along with the …

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Electron-Beam-Induced Patterned Deposition Of Allylcyclopentadienyl Palladium Using Scanning Tunneling Microscopy, D.S. Saulys, A. Ermakov, E.L. Garfunkel, Peter A. Dowben Dec 1994

Electron-Beam-Induced Patterned Deposition Of Allylcyclopentadienyl Palladium Using Scanning Tunneling Microscopy, D.S. Saulys, A. Ermakov, E.L. Garfunkel, Peter A. Dowben

Peter Dowben Publications

Scanning tunneling microscopy has been used to study the electron-induced decomposition of allylcyclopentadienyl palladium [Pd(η3-C3H5)( η5-C5H5)] and subsequent deposition on a Si(111) surface. Deposition occurs via an electron impact mechanism on either the tip or surface, depending on the bias polarity, and is observed with voltages of 2.75 V. This is close to the predicted condensed phase dissociation energy of 2.3 eV for Pd(η3-C3H5)(η5-C5H5)→Pd+C3H5+C5H5. Metallic deposits of nanometer …

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Small Polarons And The Electronic Properties Of Mo2S3, Adilgiry A. Kusov, Roger D. Kirby Dec 1994

Small Polarons And The Electronic Properties Of Mo2S3, Adilgiry A. Kusov, Roger D. Kirby

Department of Physics and Astronomy: Faculty Publications

We investigate the small-polaron mechanism as a possible explanation of electrical-conduction and electrical-noise properties of the linear chain material Mo2S3. Experimental conductivity and noise data obtained in earlier papers [Phys. Rev. B 38, 3973 (1988); Phys. Rev. B 39, 5139 (1989)] are analyzed in terms of a small-polaron mechanism and double-well potential model. We interpret the observed electronic properties in terms of kinetic equations describing the interaction of free carriers with fluctuations of density of the lattice. Appropriate kinetics equations to describe this interaction, which leads to small-polaron formation, are derived. These equations are found to …

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Aligned Two-Phase Magnets: Permanent Magnetism Of The Future? (Invited), Ralph Skomski Nov 1994

Aligned Two-Phase Magnets: Permanent Magnetism Of The Future? (Invited), Ralph Skomski

Ralph Skomski Publications

Micromagnetic calculations are used to investigate coercivity and energy products of magnets consisting of an aligned hard-magnetic skeleton phase and a soft-magnetic phase with high saturation magnetization. Compared to the present-day theoretical limit of 516 W/m3 for single-phase Nd2Fe14B, the energy product in suitable nanostructured Sm2Fe2N3/Fe65Co35 composites is predicted to be as high as 1090 kJ/m3. The influence of the skeleton’s texture and shape is discussed, and aligned nanocrystalline two-phase magnets are compared with remanence-enhanced isotropic magnets. In particular, it is shown how the nucleation-based analytical …

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Mössbauer Study Of Permanent-Magnet Materials: Sm2Fe17-XAlX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer Nov 1994

Mössbauer Study Of Permanent-Magnet Materials: Sm2Fe17-XAlX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer

David Sellmyer Publications

The Fe57 Mössbauer spectra of Sm2Fe17-xAlx, where x=0, 1.0, 2.0, 3.0, and 4.0, have been measured at room temperature and analyzed. The ternary compounds Sm2Fe17-xAlx have the rhombohedral Th2Zn17 structure. Mössbauer measurements showed that all the compounds studied were ferromagnetic. The average hyperfine field was found to decrease with the increasing aluminum concentration, which is in qualitative agreement with magnetic measurements. The decrease in the average hyperfine field was from 224 kOe at x=0 to 174 kOe at x=4. By fitting the …

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Sputtering Pressure Effects And Temperature-Dependent Magnetism Of Co/Pd Multilayers, S.Y. Jeong, Z.S. Shan, P. He, J.X. Shen, Y.B. Zhang, John A. Woollam, David J. Sellmyer Nov 1994

Sputtering Pressure Effects And Temperature-Dependent Magnetism Of Co/Pd Multilayers, S.Y. Jeong, Z.S. Shan, P. He, J.X. Shen, Y.B. Zhang, John A. Woollam, David J. Sellmyer

David Sellmyer Publications

The temperature dependence of the sputtering Ar pressure effects on magnetic properties and the coercivity mechanism of Co(2 Å)/Pd(13 Å) multilayers were studied as the sputtering Ar pressure varied from 3–15 mTorr and the temperature from 300 to 35 K. It is found that the roughness of the interfaces or film surface increases with increasing sputtering pressure, the anisotropy increases with decreasing temperature and increasing Ar pressure and shows a maximum at PAr≃12 mTorr, and the coercivity increases with Ar pressure and shows stronger temperature dependence at higher Ar pressure. The coercivity mechanism was analyzed in terms of …

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Interface Alloying And Magnetic Properties Of Fe/Rh Multilayers, K. Hanisch, W. Keune, R.A. Brand, Christian Binek, Wolfman Kleemann Nov 1994

Interface Alloying And Magnetic Properties Of Fe/Rh Multilayers, K. Hanisch, W. Keune, R.A. Brand, Christian Binek, Wolfman Kleemann

Christian Binek Publications

Rh(20 Å)/57Fe(tFe) multilayers with Fe thicknesses tFe of 2, 5, 10, and 15 Å prepared by alternate evaporation in UHV have been investigated by x-ray diffraction (XRD), Mössbauer spectroscopy, and SQUID magnetometry. First- and second-order superstructure Bragg peaks (but no higher-order peaks) in small-angle XRD patterns suggest some compositional modulation. Mössbauer spectra taken at 4.2 K are characterized by a distribution P(Bhf) of hyperfine fields Bhf. Peaks observed in the P(Bhf) curves near 17 and 35 T are assigned to an fcc-RhFe interface alloy (~7–24 at. % Fe) with …

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Thickness Dependence Of The Magnetic And Electrical Properties Of Fe:Sio2 Nanocomposite Films, S.S. Malhotra, Yi Liu, J.X. Shen, Sy_Hwang Liou, David J. Sellmyer Nov 1994

Thickness Dependence Of The Magnetic And Electrical Properties Of Fe:Sio2 Nanocomposite Films, S.S. Malhotra, Yi Liu, J.X. Shen, Sy_Hwang Liou, David J. Sellmyer

Sy-Hwang Liou Publications

Nanocomposite Fe80 (SiO2)20 films with thickness from 150 to 5000 Å have been prepared by rf magnetron sputtering from a composite target. The crystallites in the Fe80 (SiO2)20 films have a bcc structure with the average size of 46–66 Å which was determined by transmission electron microscopy. As indicated by the thickness dependence of resistivity, the stacking and connectivity of the crystallites depend on the thickness of the films. The magnetic properties also depend on the microstructure which changes with the thickness of the films. The magnetic coercivity of the films increases …

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Mössbauer, Magnetic, And Electronic-Structure Studies Of Yfe12-XMoX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer, H.H. Hamdeh Nov 1994

Mössbauer, Magnetic, And Electronic-Structure Studies Of Yfe12-XMoX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer, H.H. Hamdeh

David Sellmyer Publications

Mössbauer spectra, magnetization measurements, and self-consistent spin-polarized electronic structures of YFe12-xMox, where x=0.5, 1.0, 2.0, 3.0, and 4.0, are reported. The ternary compounds YFe12-xMox have the crystalline tetragonal ThMn12 structure. Analyses of the Mössbauer spectra show that Mo atoms occupy the 8i Fe sites of the ThMn12 structure, in agreement with previous observations. Room-temperature magnetic and Mössbauer measurements show that the compounds with x≤2.0 are ferromagnetic and with x≥3.0 are paramagnetic. Measurements at 25 K show that all the samples are magnetically ordered. The magnetic hyperfine field is …

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Anisotropy And Magneto-Optical Properties Of Sputtered Co/Ni Multilayer Thin Films, Y.B. Zhang, John A. Woollam, Z.S. Shan, J.X. Shen, David J. Sellmyer Nov 1994

Anisotropy And Magneto-Optical Properties Of Sputtered Co/Ni Multilayer Thin Films, Y.B. Zhang, John A. Woollam, Z.S. Shan, J.X. Shen, David J. Sellmyer

David Sellmyer Publications

Several series of sputtered Co/Ni multilayer thin films have been investigated. The volume and interface contributions to the magnetic anisotropy were determined from magnetization measurements, and the interface anisotropy, Ki= 0.23 ± 0.03 erg/cm2, was found to support perpendicular magnetic anisotropy. The anisotropy constant, K, increased with the Au buffer layer thickness, indicating the buffer layer was crucial to the perpendicular magnetic anisotropy. The polar Kerr rotation and coercivity as a function of temperature, and room temperature magneto-optical figure of merit are presented in this paper.

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Binary-Encounter-Dipole Model For Electron-Impact Ionization, Yong-Ki Kim, M. Eugene Rudd Nov 1994

Binary-Encounter-Dipole Model For Electron-Impact Ionization, Yong-Ki Kim, M. Eugene Rudd

M. Eugene Rudd Publications

A theoretical model, which is free of adjustable or fitted parameters, for calculating electron impact ionization cross sections for atoms and molecules is presented. This model combines the binary-encounter theory with the dipole interaction of the Bethe theory for fast incident electrons. The ratios of the contributions from distant and close collisions and interference between the direct and exchange terms are determined by using the asymptotic behaviors predicted by the Bethe theory for ionization and for stopping cross sections. Our model prescribes procedures to calculate the singly differential cross section (energy distribution) for each subshell using the binding energy, average …

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Nanostructures Of Sm-Co On Cr Thin Films, Yi Liu, B. W. Robertson, Z.S. Shan, S. Malhotra, M.J. Yu, S.K. Renukunta, Sy_Hwang Liou, David J. Sellmyer Nov 1994

Nanostructures Of Sm-Co On Cr Thin Films, Yi Liu, B. W. Robertson, Z.S. Shan, S. Malhotra, M.J. Yu, S.K. Renukunta, Sy_Hwang Liou, David J. Sellmyer

Sy-Hwang Liou Publications

The nanostructures of Sm-Co on Cr thin films prepared by dc magnetron sputtering were investigated by high resolution transmission electron microscopy (HRTEM) and diffraction techniques. HRTEM micrographs show that the crystallites in the Sm-Co films, as revealed by the lattice fringes, are distributed discontinuously in the matrix. The matrix is amorphous as indicated by the microdiffraction study. The size of the crystallites is in the range of 2~5 nanometers. The volume fraction of the crystallites in the film decreases from 91% to 54% as the argon pressure is increased from 5 mTorr to 30 mTorr. Micrographs recorded in a bright …

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Resonant Photoemission Studies Of Thickness Dependence Of The Unoccupied Gd 5d Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion Oct 1994

Resonant Photoemission Studies Of Thickness Dependence Of The Unoccupied Gd 5d Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion

Peter Dowben Publications

Ultrathin Gd films have been studied with constant initial-state spectroscopy (CIS) of photoemission utilizing linearly polarized light of synchrotron radiation. The photoemission cross-section of the 5d surface state near EF shows strong photon energy dependence, i.e., sharp peaks in CIS spectra near the Gd 5p1/2 adsorption edge. These peaks originate from resonant photoemission processes involving the occupied 5p and unoccupied 5d levels of the surface atoms. The symmetry of the unoccupied states were determined experimentally by changing the polarization of light, where p-polarized light excites only to the unoccupied dz2 or dxz,yz states and s-polarized light …

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Novel Methods For The Fabrication Of Ferromagnetic Nickel And Nickel Boride Thin Films, D. Zych, A. Patwa, S.S. Kher, N.M. Boag, Peter A. Dowben Sep 1994

Novel Methods For The Fabrication Of Ferromagnetic Nickel And Nickel Boride Thin Films, D. Zych, A. Patwa, S.S. Kher, N.M. Boag, Peter A. Dowben

Peter Dowben Publications

Metal-rich nickel boride thin films fabricated from boron-containing precursor compounds by a cluster deposition process are shown to be ferromagnetic. The metal-rich films fabricated by this approach exhibit hysteresis curves similar to those obtained for pure nickel foils. These films are a mixture of pure nickel and the Ni3B nickel boride phases. It is postulated that the hysteresis curves with smaller remnant magnetizations obtained from these films are a consequence of Ni3B inclusions within the films. Other novel organometallic source compounds for nickel chemical-vapor deposition are briefly reviewed. Journal of Applied Physics is copyrighted by The …

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Clean Ultrahigh Vacuum System With Single-Structure Diffusion Pumps, Timothy J. Gay, M.C. Fritts, J.E. Furst, M.A. Khakoo, E.R. Mell, M.T. Seiger, M.W.K.P. Wijayaratna Sep 1994

Clean Ultrahigh Vacuum System With Single-Structure Diffusion Pumps, Timothy J. Gay, M.C. Fritts, J.E. Furst, M.A. Khakoo, E.R. Mell, M.T. Seiger, M.W.K.P. Wijayaratna

Timothy J. Gay Publications

A practical example of the use of single-structure diffusion pumping groups in an experiment requiring hydrocarbon-free, ultrahigh vacuum is presented. With the use of proper vacuum procedures and careful foreline design and operation, but with no exotic hardware or liquid nitrogen, we have demonstrated that such a pump could provide vacuum that was "clean," i.e., which had no residual pump-oil contamination to a partial pressure below 10-8 mbar. Their use is thus compatible, at least in peripheral vacuum chambers, with standard "UHV-surface science" processes. We discuss our vacuum system in detail, and present a review of the literature on …

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Clean Ultrahigh Vacuum System With Single-Structure Diffusion Pumps, Timothy J. Gay, M.C. Fritts, J.E. Furst, M.A. Khakoo, E.R. Mell, M.T. Seiger, M.W.K.P. Wijayaratna Sep 1994

Clean Ultrahigh Vacuum System With Single-Structure Diffusion Pumps, Timothy J. Gay, M.C. Fritts, J.E. Furst, M.A. Khakoo, E.R. Mell, M.T. Seiger, M.W.K.P. Wijayaratna

Timothy J. Gay Publications

A practical example of the use of single-structure diffusion pumping groups in an experiment requiring hydrocarbon-free, ultrahigh vacuum is presented. With the use of proper vacuum procedures and careful foreline design and operation, but with no exotic hardware or liquid nitrogen, we have demonstrated that such a pump could provide vacuum that was "clean," i.e., which had no residual pump-oil contamination to a partial pressure below 10-8 mbar. Their use is thus compatible, at least in peripheral vacuum chambers, with standard "UHV-surface science" processes. We discuss our vacuum system in detail, and present a review of the literature on the …

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Superelastic And Inelastic He2++He State-Selective Electron Capture, V. D. Irby, Timothy J. Gay, J. T. Park, S. W. Bross, A. D. Gaus Sep 1994

Superelastic And Inelastic He2++He State-Selective Electron Capture, V. D. Irby, Timothy J. Gay, J. T. Park, S. W. Bross, A. D. Gaus

Timothy J. Gay Publications

Experimental studies have been made of superelastic and inelastic collision processes involved in the state-selective single-electron capture reaction 3He2++He(1 1S)→ +He+(n)+He+(n’), where n and n’ are the final principal quantum-number states of the collision products. Total cross sections have been measured at projectile energies of 15, 30, and 45 keV/u, by examining the energy loss-gain of the fast 3He+ product ions, for the superelastic n=n’=1 channel, and for the sum of the inelastic n=2, n’=1 and n=1, n’=2 states. Measurements …

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Dissociative Attachment In Selected Monochloroalkanes, D. M. Pearl, Paul Burrow Aug 1994

Dissociative Attachment In Selected Monochloroalkanes, D. M. Pearl, Paul Burrow

Paul Burrow Publications

The total cross sections for the dissociative attachment (DA) process are reported for eight normal chloroalkanes CnH2n+1Cl for n=2–9, two secondary compounds 2-chloropropane and 2-chlorobutane, one tertiary compound t-butyl chloride, and three cyclic chloroalkanes c-CnH2n-1Cl for n=4–6, for electron energies below 4 eV. Using vertical attachment energies (VAEs) determined by electron transmission spectroscopy elsewhere and in this work, we show that the resonance widths vary linearly with VAE in this series of compounds and that the peak DA cross sections decline exponentially with increasing VAE. …

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Reply To D. E. Watt, A. S. Alkharam, M. B. Child And M. S. Salikin, “Dose As A Damage Specifier In Radiobiology For Radiation Protection." A Comment On "Dose" (Radiat. Res. 137, 410-413, 1994), Robert Katz Aug 1994

Reply To D. E. Watt, A. S. Alkharam, M. B. Child And M. S. Salikin, “Dose As A Damage Specifier In Radiobiology For Radiation Protection." A Comment On "Dose" (Radiat. Res. 137, 410-413, 1994), Robert Katz

Robert Katz Publications

The authors are generous in observing that "the high degree of success achieved by (Katz's δ-ray theory of track structure) in fits to survival curves for heavy ions, and in analysis and prediction of other biological effects is almost legend." We remind them that the model is physical, and has little to do with biology in an explicit way, except that an oversimplified "bean bag" model of a eukaryotic cell is used, in which the bag represents the cell nucleus and the beans represent internal targets. No explicit biologically mechanistic structure or response is inferred. No reference is made to …

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Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben Jul 1994

Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben

Peter Dowben Publications

Using photoelectron spectroscopy, the overlayer electronic structure was observed to he modulated by the Hg growth mode for Hg adsorbed on W(110) at 200 K. The Hg layer-by-layer growth was also characterized by variations in the ratio between the Hg 5d shallow core level and W 4f photoemission intensities. This layer-by-layer growth occurs in spite of surprisingly weak electronic interactions between the adatoms and the substrate.

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Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben Jul 1994

Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben

Peter Dowben Publications

Using photoelectron spectroscopy, the overlayer electronic structure was observed to he modulated by the Hg growth mode for Hg adsorbed on W(110) at 200 K. The Hg layer-by-layer growth was also characterized by variations in the ratio between the Hg 5d shallow core level and W 4f photoemission intensities. This layer-by-layer growth occurs in spite of surprisingly weak electronic interactions between the adatoms and the substrate.

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On The Linear Extrapolation To Low Doses, Robert Katz, Michael P. R. Waligórski Jun 1994

On The Linear Extrapolation To Low Doses, Robert Katz, Michael P. R. Waligórski

Robert Katz Publications

While radiobiological data are conveniently fitted by a linear quadratic formula to data of limited dynamic range at doses typically exceeding 1 Gy, they are extrapolated linearly to doses below a milligray for the evaluation of low dose RBEs. However a single relativistic electron passing through a cell nucleus deposits a “dose” there in the neighborhood of a milligray. The validity of the linear extrapolation then rests on the demonstration that a single electron transit through a cell nucleus can cause inactivation or mutation or can lead to cancer induction. The extrapolation made is a huge one, of some three …

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Photoconductivity And Grating Response Time Of A Photorefractive Polymer, Brian E. Jones, Stephen Ducharme, Martin M Liphardt, Arosha Goonesekera, James M. Takacs, Lei Zhang, Rajan Athalye Jun 1994

Photoconductivity And Grating Response Time Of A Photorefractive Polymer, Brian E. Jones, Stephen Ducharme, Martin M Liphardt, Arosha Goonesekera, James M. Takacs, Lei Zhang, Rajan Athalye

Stephen Ducharme Publications

We report the photoconductive properties and photorefractive grating response time of a polymer mixture composed of 40-wt. % dissolved diethylamino-benzaldehyde diphenyl hydrazone (DEH) and the non-cross-linking epoxy polymer Bisphenol A 4,4'-nitroaminostilbene. The films have improved photoconductive sensitivities as high as 2.1 × 10–10 cm/(W Ω) at a wavelength of 650 nm with a corresponding reduction of the grating response time constant to 0.11 ± 0.02 s at an intensity of 1 W/cm2. The nitro-aminostilbene chromophore is deduced to be the source of photogenerated charge carriers on the basis of a comparison of the wavelength dependence of the …

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Magnetic And Magneto-Optical Properties Of Mn5(Ge1-XMX)3 Alloys With M=Sn, Pb, Y. Zhang, A.P. Runge, Z.S. Shan, David J. Sellmyer May 1994

Magnetic And Magneto-Optical Properties Of Mn5(Ge1-XMX)3 Alloys With M=Sn, Pb, Y. Zhang, A.P. Runge, Z.S. Shan, David J. Sellmyer

David Sellmyer Publications

We report on the magnetic and magneto-optical properties of the intermetallic alloys Mn5(Ge1-xMx)3, where M=Sn, Pb. Generally, these alloys were ordered ferromagnetically at T≥300 K for x<0.3. The structure of Mn5(Ge1-xSnx)3 remains in the hexagonal Mn5Si3 (hP16) phase up to x=0.25 and then changes to Ni2In (hP6) as x approaches 1. The magnetization and Curie temperature of these alloys is largest for small x and reach a minimum value near x=0.5. The room temperature Polar Kerr rotation, however, …

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Electronic Structure And Curie Temperature Of Yfe12-XMoXNY Compounds, A.S. Fernando, J.P. Woods, Sitaram Jaswal, D. Welipitiya, B.M. Patterson, David J. Sellmyer May 1994

Electronic Structure And Curie Temperature Of Yfe12-XMoXNY Compounds, A.S. Fernando, J.P. Woods, Sitaram Jaswal, D. Welipitiya, B.M. Patterson, David J. Sellmyer

David Sellmyer Publications

The electronic structures of YFe12-xMoxNy , where x=1.0, 2.0 and y=0, 0.7, have been studied with photoemission and spin-polarized calculations. The peak near the Fermi level in the energy distribution curves (EDC) becomes successively broader with larger Mo concentration. The features in the calculated density of state at 1.3 and 2.7 eV are not readily seen in the EDC, and this may be due to lifetime effects in these compounds. Finally, changes in Curie temperature (Tc) with the change of N or Mo concentration are compared with prediction of the …

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Magnetic Properties Of Nd(Fe,Ti) 12 And Nd(Fe,Ti) 12NX Films Of Perpendicular Texture, D. Wang, David J. Sellmyer, I. Panagiotopoulos, D. Niarchos May 1994

Magnetic Properties Of Nd(Fe,Ti) 12 And Nd(Fe,Ti) 12NX Films Of Perpendicular Texture, D. Wang, David J. Sellmyer, I. Panagiotopoulos, D. Niarchos

David Sellmyer Publications

Nd(Fe,Ti)12 and Nd(Fe,Ti)12Nx films textured with c axis perpendicular to the film plane were synthesized by sputtering. For the Nd(Fe,Ti)12 films a spin reorientation took place at about 170 K. For the Nd(Fe,Ti)12Nx films, the anisotropy field is about 85 kOe at room temperature and 130 kOe at 5 K, corresponding to a coercivity of 2.7 and 12 kOe, respectively. Initial magnetization curves show a behavior characteristic of nucleation type of magnetization reversal mechanism. Attempts were made to fit the experimental data with Kronmüller's magnetization reversal model. The results suggest that nucleation …

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Magneto-Optical And Structural Properties Of Bialdylg/Fe Multilayers, J. X. Shen, Kurt W. Wierman, Y. B. Zhang, Roger D. Kirby, John A. Woollam, David J. Sellmyer May 1994

Magneto-Optical And Structural Properties Of Bialdylg/Fe Multilayers, J. X. Shen, Kurt W. Wierman, Y. B. Zhang, Roger D. Kirby, John A. Woollam, David J. Sellmyer

Roger Kirby Publications

Bi- and Al-doped DyIG(y Å)/Fe(x Å) (y = 50 to 130 Å and x = 5 to 15 Å ) multilayer thin films were made by magnetron sputtering onto Si(111) substrates. Rapid thermal annealing was used to crystallize these garnet multilayers. The crystallized multilayer samples possess well-defined interfaces. Atomic force microscopy showed that the annealed samples had smooth surfaces, with small grain sizes (~30 to 80 nm). All of the samples had perpendicular magnetic anisotropy with very square hysteresis loops. The coercivity was found to vary from 600 Oe to 2 kOe, depending on Fe thickness and annealing …

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Temperature-Dependent Interface Magnetism And Magnetization Reversal In Co/Pt Multilayers, Z. S. Shan, J. X. Shen, Roger D. Kirby, David J. Sellmyer, Y. J. Wang May 1994

Temperature-Dependent Interface Magnetism And Magnetization Reversal In Co/Pt Multilayers, Z. S. Shan, J. X. Shen, Roger D. Kirby, David J. Sellmyer, Y. J. Wang

Roger Kirby Publications

We report on the temperature dependence of the magnetic properties and interface magnetism of Co/Pt multilayers. The magnetic properties including magnetization and anisotropy change substantially as the temperature varies from 300 to 10 K for samples with Co layer thickness in the range from 3 to 7 Å. The interface anisotropy of about 0.38 erg/cm2 is nearly independent of temperature. The magnetization reversal is dominated by domain wall motion for the thinner Co layers and dominated by nucleation for the thicker Co layers.

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Magnetic And Magneto-Optic Properties Of Sputtered Co/Ni Multilayers, Y. B. Zhang, P. He, John A. Woollam, J. X. Shen, Roger D. Kirby, David J. Sellmyer May 1994

Magnetic And Magneto-Optic Properties Of Sputtered Co/Ni Multilayers, Y. B. Zhang, P. He, John A. Woollam, J. X. Shen, Roger D. Kirby, David J. Sellmyer

Roger Kirby Publications

We have investigated the magnetic and magneto-optic properties of Co/Ni multilayers deposited on Ag and Au buffer layers. The samples with Au buffer layers show perpendicular magnetic anisotropy, but those with Ag buffer layers do not. The. structure and degree of crystalline alignment of the buffer layer are evidently crucial to development of perpendicular magnetic anisotropy. We also present the results of polar Kerr rotation measurements as a function of wavelength and layer thickness of the multilayers.

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Changes In Electron Localization And Density Of States Near EF Across The Nonmetal-Metal Transition In Mg Overlayers, Jiandi Zhang, D.N. Mcilroy, Peter A. Dowben May 1994

Changes In Electron Localization And Density Of States Near EF Across The Nonmetal-Metal Transition In Mg Overlayers, Jiandi Zhang, D.N. Mcilroy, Peter A. Dowben

Peter Dowben Publications

A nonmetal-to-metal transition in Mg monolayers on Mo(112) has been indicated by photoemission and resonant photoemission. The dramatic changes of the density of states, the dispersion of bands near EF, and screening are observed across the nonmetal-to-metal transition. The changes of the resonance photon energy and the intensity of Mg 2p→εd excitation, with different coverages, indicate that there exists a correlation between the electronic structure (particularly final-state screening effects) and the overlayer structure. The commensurate-to-incommensurate transition beyond 0.5 monolayer of coverage corresponds to the overlayer nonmetal-to-metal transition, which is due to the hybridization of Mg s and p …

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