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Renormalization Scale Invariant Pqcd Predictions For R(E+ E-) And The Bjorken Sum Rule At Next-To-Leading Order, Michael Binger, Chueng-Ryong Ji, David G. Robertson May 2000

Renormalization Scale Invariant Pqcd Predictions For R(E+ E-) And The Bjorken Sum Rule At Next-To-Leading Order, Michael Binger, Chueng-Ryong Ji, David G. Robertson

Physics Faculty Scholarship

We discuss the application of the physical QCD effective charge αV, defined via the heavy-quark potential, in perturbative calculations at next-to-leading order. When coupled with the Brodsky-Lepage-Mackenzie prescription for fixing the renormalization scales, the resulting series are automatically and naturally scale and scheme independent, and represent unambiguous predictions of perturbative QCD. We consider in detail such commensurate scale relations for the e+e− annihilation ratio Re+e− and the Bjorken sum rule. In both cases the improved predictions are in excellent agreement with experiment.

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Low Temperature Anomaly In Mesoscopic Kondo Wires, P. Mohanty, Richard A. Webb May 2000

Low Temperature Anomaly In Mesoscopic Kondo Wires, P. Mohanty, Richard A. Webb

Faculty Publications

We report the observation of an anomalous magnetoresistance in extremely dilute quasi-one-dimensional AuFe wires at low temperatures, along with a hysteretic background at low fields. The Kondo resistivity does not show the unitarity limit down to the lowest temperature, implying uncompensated spin states. We suggest that the anomalous magnetoresistance may be understood as the interference correction from the accumulation of geometric phase in the conduction electron wave function around the localized impurity spin.

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Sulfite: Cytochrome C Oxidoreductase From Thiobacillus Novellus, Ulrike Kappler, Brian Bennett, Jörg Rethmeier, Günter Schwarz, Rainer Deutzmann, Alistair G. Mcewan, Christiane Dahl May 2000

Sulfite: Cytochrome C Oxidoreductase From Thiobacillus Novellus, Ulrike Kappler, Brian Bennett, Jörg Rethmeier, Günter Schwarz, Rainer Deutzmann, Alistair G. Mcewan, Christiane Dahl

Physics Faculty Research and Publications

Direct oxidation of sulfite to sulfate occurs in various photo- and chemotrophic sulfur oxidizing microorganisms as the final step in the oxidation of reduced sulfur compounds and is catalyzed by sulfite: cytochrome c oxidoreductase (EC1.8.2.1). Here we show that the enzyme from Thiobacillus novellus is a periplasmically located αβ heterodimer, consisting of a 40.6-kDa subunit containing a molybdenum cofactor and an 8.8-kDa mono-heme cytochrome c 552 subunit (midpoint redox potential, E m8.0 = +280 mV). The organic component of the molybdenum cofactor was identified as molybdopterin contained in a 1:1 ratio to the Mo content of the enzyme. Electron …

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“The Way Of The Scientist Deepens Beauty By Increasing Understanding”: Teaching Physics As An Aesthetic Form, Claudine Indigo Kavanagh May 2000

“The Way Of The Scientist Deepens Beauty By Increasing Understanding”: Teaching Physics As An Aesthetic Form, Claudine Indigo Kavanagh

Dissertations and Theses

Educators have struggled to find an appropriate and efficacious method to engage students of science in their classrooms and lecture halls, This investigation presents a theoretical foundation for the use of aesthetic criteria when teaching physics in high school or undergraduate settings and suggests that this may be an effective learning tool. The relationship between science aesthetics and science literacy is pursued here. Included in this study are discussions of the applications of aesthetic judgement by theoretical physicists in the 20th century and and methods for bringing a dialogue concerning natural philosophy and beauty in the science classroom. While many …

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A Spectroscopic Redshift For The Cl 0024+16 Multiple Arc System: Implications For The Central Mass Distribution, Tom Broadhurst, Xiaosheng Huang, Brenda Frye, Richard Ellis May 2000

A Spectroscopic Redshift For The Cl 0024+16 Multiple Arc System: Implications For The Central Mass Distribution, Tom Broadhurst, Xiaosheng Huang, Brenda Frye, Richard Ellis

Physics and Astronomy

We present a spectroscopic redshift of z = 1.675 for the well-known multiply lensed system of arcs seen in the z = 0.39 cluster Cl 0024+16. In contrast to earlier work, we find that the lensed images are accurately reproduced by a projected mass distribution which traces the locations of the brightest cluster elliptical galaxies, suggesting that the most significant minima of the cluster potential are not dynamically erased. The averaged mass profile is shallow and consistent with predictions of recent numerical simulations. The source redshift enables us to determine an enclosed cluster mass of M(<100 kpc h-1) = …

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Snapover: Anomalous Plasma Current Collection By Positively Biased Conductors When Surrounded By A Dielectric, Clint Thomson, John R. Dennison May 2000

Snapover: Anomalous Plasma Current Collection By Positively Biased Conductors When Surrounded By A Dielectric, Clint Thomson, John R. Dennison

All Physics Faculty Publications

Over the last decade, high-powered spacecraft have been designed that will operate at voltages greater than 100 V. At these voltages, the solar arrays can undergo both destructive arcing at negative biases, and plasma electron current collection at positive biases. Furthermore, above some critical positive bias voltage (~100 V), the electron current collected by the array interconnects increases dramatically through a phenomenon termed Asnapover@. During snapover, large portions of the solar array cover glass charge positively, and begin to draw electron current from the plasma as if it were a conducting surface. This leads to substantial power losses for the …

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Forward Ion Acceleration In Thin Films Driven By A High-Intensity Laser, Anatoly Maksimchuk, S. Gu, K. Flippo, Donald P. Umstadter, V. Yu. Bychenkov May 2000

Forward Ion Acceleration In Thin Films Driven By A High-Intensity Laser, Anatoly Maksimchuk, S. Gu, K. Flippo, Donald P. Umstadter, V. Yu. Bychenkov

Donald Umstadter Publications

A collimated beam of fast protons, with energies as high as 1.5 MeV and total number of ≳109, confined in a cone angle of 40°±10° is observed when a high-intensity high-contrast subpicosecond laser pulse is focused onto a thin foil target. The protons, which appear to originate from impurities on the front side of the target, are accelerated over a region extending into the target and exit out the back side in a direction normal to the target surface. Acceleration field gradients ∼10 GeV/cm are inferred. The maximum proton energy can be explained by the charge-separation electrostatic-field acceleration …

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Fept:Sio2 Granular Thin Film For High Density Magnetic Recording, C.P. Luo, Sy_Hwang Liou, David J. Sellmyer May 2000

Fept:Sio2 Granular Thin Film For High Density Magnetic Recording, C.P. Luo, Sy_Hwang Liou, David J. Sellmyer

Sy-Hwang Liou Publications

Nanocomposite FePt:SiO2 thin films consisting of high anisotropy FePt particles embedded in a SiO2 matrix have been successfully fabricated by annealing the as-deposited FePt/SiO2 multilayers. By adjusting the annealing temperatures and compositions, films were obtained with coercivity of 3.8 kOe and grain size of 10 nm, which are suitable for high-density magnetic recording. Magnetic activation volumes were measured and thermal stability is discussed.

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Effects Of Ga Substitution For Fe On The Structure And Magnetic Properties Of Nd8.4Fe87.1-XGaXB4.5 (X = 0–2.2) Alloys Prepared By Mechanical Alloying, B.Z. Cui, X.K. Sun, W. Liu, Z.D. Zhang, D.Y. Geng, X.G. Zhao, J. Ping Liu, David J. Sellmyer May 2000

Effects Of Ga Substitution For Fe On The Structure And Magnetic Properties Of Nd8.4Fe87.1-XGaXB4.5 (X = 0–2.2) Alloys Prepared By Mechanical Alloying, B.Z. Cui, X.K. Sun, W. Liu, Z.D. Zhang, D.Y. Geng, X.G. Zhao, J. Ping Liu, David J. Sellmyer

David Sellmyer Publications

The effects of a partial substitution of Ga for Fe on the structure and magnetic properties of mechanically alloyed Nd8.4Fe87.1B4.5 were studied. With increasing Ga content, the magnetic properties of the nanocomposite magnets first improve, reach maxima at 1.1 at.% Ga, and then degrade. The addition of Ga helps to control the morphology, especially the grain sizes of both α -Fe and Nd2Fe14B.

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Curie Temperature Of Multiphase Nanostructures, Ralph Skomski, David J. Sellmyer May 2000

Curie Temperature Of Multiphase Nanostructures, Ralph Skomski, David J. Sellmyer

David Sellmyer Publications

The Curie temperature and the local spontaneous magnetization of ferromagnetic nanocomposites are investigated. The macroscopic character of the critical fluctuations responsible for the onset of ferromagnetic order means that there is only one Curie temperature, independent of the number of magnetic phases present. The Curie temperature increases with the grain size and is, in general, larger than predicted from the volume averages of the exchange constants. However, the Curie-temperature enhancement is accompanied by a relative reduction of the spontaneous magnetization. Due to the quadratic dependence of the permanent-magnet energy product on the spontaneous magnetization, this amounts to a deterioration of …

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Doomsday Fears At Rhic, Thomas D. Gutierrez May 2000

Doomsday Fears At Rhic, Thomas D. Gutierrez

Physics

This year, the Relativistic Heavy Ion Collider (RHIC) is poised to begin a program of cutting-edge nuclear science. Recently, alarmist journalism unnecessarily raised public fears about implausible doomsday scenarios associated with the machine.

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Oxygen-Induced Positive Spin Polarization From Fe In The Vacuum Barrier, Evgeny Y. Tsymbal, Ivan I. Oleinik, David G. Pettifor May 2000

Oxygen-Induced Positive Spin Polarization From Fe In The Vacuum Barrier, Evgeny Y. Tsymbal, Ivan I. Oleinik, David G. Pettifor

Evgeny Tsymbal Publications

Bonding at the ferromagnet–insulator interface is an important factor which influences spin polarization of the tunneling current in ferromagnetic tunnel junctions. In this article we investigate the spin-polarized electronic structure of the (001) surface of body-centered-cubic iron covered by an oxygen overlayer, as this could reflect the mechanism of bonding and spin polarization in iron/oxide tunnel junctions. The Fe/O atomic structure is optimized using the plane-wave code CASTEP within the spin-polarized generalized-gradient approximation. The electronic structure and local densities of states are calculated using the linear muffin-tin orbital method. The results show hybridization of the iron 3d orbitals with …

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Origin Of The Magnetic Moments In La0.65Pb0.35Mno3 Epitaxial Thin Films, C.N. Borca, R.H. Cheng, Q.L. Xu, Sy_Hwang Liou, Shane Stadler, Y.U. Idzerda, Peter A. Dowben May 2000

Origin Of The Magnetic Moments In La0.65Pb0.35Mno3 Epitaxial Thin Films, C.N. Borca, R.H. Cheng, Q.L. Xu, Sy_Hwang Liou, Shane Stadler, Y.U. Idzerda, Peter A. Dowben

Peter Dowben Publications

Crystalline films of La0.65Pb0.35MnO3 grown on (100) LaAlO 3 substrates by rf sputtering have been investigated using magnetic circular dichroism and inverse photoemission spectroscopy. We find evidence for strong hybridization between unoccupied levels associated with Mn 3d and O 2p states. The oxygen atoms "pick-up" a small magnetic moment through hybridization with Mn. ©2000 American Institute of Physics

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Structure And Magnetic Properties Of N-Containing Nd–Fe–B Alloys Prepared By Mechanical Alloying, W. Liu, Z.D. Zhang, J. Ping Liu, X.K. Sun, David J. Sellmyer May 2000

Structure And Magnetic Properties Of N-Containing Nd–Fe–B Alloys Prepared By Mechanical Alloying, W. Liu, Z.D. Zhang, J. Ping Liu, X.K. Sun, David J. Sellmyer

David Sellmyer Publications

The structure and magnetic properties of Nd2Fe14BNδ -based alloys prepared by mechanical alloying have been investigated. For the Nd14Fe78B8Ny series, a large amount of NdN, α-Fe, and a small Nd2Fe14B phase are observed in x-ray diffraction patterns. With increasing Nd content, the amount of the Nd2Fe14BNδ phase increases and α-Fe decreases gradually. When x≥25 in the NdxFe92-xB8Ny systems, some amount of the N-containing, Nd-rich phase appears. Meanwhile, the content of the nitrogen …

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Magnetic Properties Of Self-Assembled Co Nanowires Of Varying Length And Diameter, H. Zeng, M. Zheng, Ralph Skomski, David J. Sellmyer, Yi Liu, L. Menon, Supriyo Bandyopadhyay May 2000

Magnetic Properties Of Self-Assembled Co Nanowires Of Varying Length And Diameter, H. Zeng, M. Zheng, Ralph Skomski, David J. Sellmyer, Yi Liu, L. Menon, Supriyo Bandyopadhyay

David Sellmyer Publications

Ferromagnetic Co nanowires have been electrodeposited into self-assembled porous anodic alumina arrays. Due to their cylindrical shape, the nanowires exhibit perpendicular anisotropy. The coercivity, remanence ratio, and activation volumes of Co nanowires depend strongly on the length, diameter, and spacing of the nanowires. Both coercivity and thermal activation volume increase with increasing wire length, while for constant center-to-center spacing, coercivity decreases and thermal activation volume increases with increasing wire diameter. The behavior of the nanowires is explained qualitatively in terms of localized magnetization reversal.

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Instrumentation And Measurement Of Secondary Electron Emission For Spacecraft Charging, Neal Nickles, John R. Dennison May 2000

Instrumentation And Measurement Of Secondary Electron Emission For Spacecraft Charging, Neal Nickles, John R. Dennison

All Physics Faculty Publications

Secondary electron emission is an important physical mechanism in the problem of spacecraft charging. The NASA Space Environments and Effects branch is currently revising NASA’s strategy for mitigating damage due to spacecraft charging. In an effort to substantially improve the modeling of spacecraft charging, measurements of secondary electron emission parameters are being made. The design of the apparatus needed to measure these parameters is discussed in detail. Various measurement techniques are explained and conclusions are drawn about the suitability of the final design.

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Helix Inversion In The Chiral Nematic And Isotropic Phases Of A Liquid Crystal, Benjamin P. Huff , '99, Jacob J. Krich , '00, Peter J. Collings May 2000

Helix Inversion In The Chiral Nematic And Isotropic Phases Of A Liquid Crystal, Benjamin P. Huff , '99, Jacob J. Krich , '00, Peter J. Collings

Physics & Astronomy Faculty Works

Measurements of the chirality (2π/pitch) in the chiral nematic phase and of a structural constant proportional to the chirality in the isotropic liquid for a system in which a helix inversion line crosses the chiral nematic to isotropic phase transition line are reported. While the chirality shows a strong temperature dependence in the chiral nematic phase, it loses all temperature dependence in the isotropic phase. In addition, the chirality in the isotropic phase is proportional to the chirality in the chiral nematic phase at the phase transition, and may in fact be continuous across the transition. While molecular field and …

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Infrared Classification Of Galactic Objects, Željko Ivezić, Moshe Elitzur May 2000

Infrared Classification Of Galactic Objects, Željko Ivezić, Moshe Elitzur

Physics and Astronomy Faculty Publications

Unbiased analysis shows that IRAS data reliably differentiate between the early and late stages of stellar evolution because objects at these stages clearly segregate in infrared color-color diagrams. Structure in these diagrams is primarily controlled by the density distribution of circumstellar dust. The density profile around older objects is the steepest, declining as r-2, while young objects have profiles that vary as r-3/2 and flatter. The different density profiles reflect the different dynamics that govern the different environments. Our analysis also shows that high-mass star formation is strongly concentrated within ~5 kpc around the Galactic center, in …

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Zno Diode Fabricated By Excimer-Laser Doping, Toru Aoki, Yoshinori Hatanaka, David C. Look May 2000

Zno Diode Fabricated By Excimer-Laser Doping, Toru Aoki, Yoshinori Hatanaka, David C. Look

Physics Faculty Publications

A ZnO diode was fabricated by using a laser-doping technique to form a p-type ZnO layer on an n-type ZnO substrate. A zinc-phosphide compound, used as a phosphorous source, was deposited on the ZnO wafer and subjected to excimer-laser pulses. The current–voltage characteristics showed a diode characteristic between the phosphorous-doped p-layer and the n-type substrate. Moreover, light emission, with a band-edge component, was observed by forward current injection at 110 K.

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Simple Model For Mixing At Accelerated Fluid Interfaces With Shear And Compression, John D. Ramshaw May 2000

Simple Model For Mixing At Accelerated Fluid Interfaces With Shear And Compression, John D. Ramshaw

Physics Faculty Publications and Presentations

A simple model was recently described for predicting linear and nonlinear mixing at an unstable planar interface between two fluids of different density subjected to an arbitrary time-dependent variable acceleration history [J. D. Ramshaw, Phys. Rev. E 58, 5834 (1998)]. Here we generalize this model to include the Kelvin-Helmholtz (KH) instability resulting from a tangential velocity discontinuity delta u, as well as the effects of a uniform anisotropic compression or expansion of the mixing layer as a whole. The model consists of a second-order nonlinear ordinary differential equation of motion for the half-width h of the mixing layer. This equation …

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Rotation-Invariant Synthetic Discriminant Function Filter For Pattern Recognition, Vahid R. Riasati, Partha P. Banerjee, Mustafa A. G. Abushagur, Kenneth B. Howell May 2000

Rotation-Invariant Synthetic Discriminant Function Filter For Pattern Recognition, Vahid R. Riasati, Partha P. Banerjee, Mustafa A. G. Abushagur, Kenneth B. Howell

Electrical and Computer Engineering Faculty Publications

The ring synthetic discriminant function (RSDF) filter for rotation-invariant response is discussed for pattern recognition. This method uses one half of a slice of the Fourier transform of the object to generate the transfer function of the filter. This is accomplished by rotating the one half of a slice in the Fourier domain through 2π rad about the zero-frequency point of the Fourier plane. This filter has the advantage of always matching at least one half of a slice of the Fourier transform of any rotation of the image. An analytical discussion of the filter construction and correlation results are …

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A Magnetic And Crystallographic Study Of (Sm/Gd)₂(Fe/Si)₁₇CZ Solid Solutions, Peter C. Ezekwenna, G. K. Marasinghe, J. H. Nam, William Joseph James, William B. Yelon, M. Ellouze, Ph. I'Héritier May 2000

A Magnetic And Crystallographic Study Of (Sm/Gd)₂(Fe/Si)₁₇CZ Solid Solutions, Peter C. Ezekwenna, G. K. Marasinghe, J. H. Nam, William Joseph James, William B. Yelon, M. Ellouze, Ph. I'Héritier

Chemistry Faculty Research & Creative Works

The crystallographic and magnetic properties of SmyGd2-yFe17-xSix (0 ≤ x ≤ 3 and y = 1 and 1.5) solid solutions and their interstitial carbides have been investigated using x-ray diffraction and magnetic measurements. The SmyGd2-yFe17-xSix samples crystallized in the rhombohedral Th2Zn17 structure with less than 5 mol % of impurities. The unit cells of the mixed rare-earth (R) samples are smaller than those of Sm2Fe17 and Gd2Fe17. The carbided samples contain up to a total of …

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The Atomic And Magnetic Structure Of Ndmn(₆₋ₓ)Feₓge₆ Solid Solutions, J. Han, G. K. Marasinghe, William Joseph James, Muguo Chen, William B. Yelon, I. Dubenko, Naushad Ali May 2000

The Atomic And Magnetic Structure Of Ndmn(₆₋ₓ)Feₓge₆ Solid Solutions, J. Han, G. K. Marasinghe, William Joseph James, Muguo Chen, William B. Yelon, I. Dubenko, Naushad Ali

Chemistry Faculty Research & Creative Works

The magnetic and crystallographic properties of induction-melted NdMn(6-x)FexGe6 intermetallics (x = 0, 1.0, and 1.5) in the temperature range of 30-475 K have been studied by x-ray and neutron diffraction techniques and SQUID measurements. All of the samples crystallized in the YCo6Ge6-type structure (P6/mmm). A small amount ( < 5 mol%) of Nd(MnFe)2Ge2 is present as an impurity. As expected, iron replaces manganese at the 3g site. The unit cell volume decreases slightly with increasing iron content at an average rate of 1.3% per substituted atom. Lattice parameters a and c contract at …

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Activation Volumes In Thin Film And Particulate Systems, Roger D. Kirby, Mingjun Yu, David J. Sellmyer May 2000

Activation Volumes In Thin Film And Particulate Systems, Roger D. Kirby, Mingjun Yu, David J. Sellmyer

Roger Kirby Publications

We consider magnetization reversal and decay in thin film and particulate magnetic systems where thermally activated processes are important. We present measurements on the activation volumes associated with magnetization reversal in CoCrPt thin films. We find that the measured activation volume V* goes through a minimum as the film thickness is decreased from 17.5 to 5.5 nm. We have modeled this behavior qualitatively by assuming that the energy barrier to thermally activated reversal varies as 1/H, as has been predicted for incoherent nucleation processes and thermally activated domain–wall motion. This model also predicts that V* varies …

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Ion-Kill Dosimetry, Robert Katz, F. A. Cucinotta, M. Fromm, A. Chambaudet May 2000

Ion-Kill Dosimetry, Robert Katz, F. A. Cucinotta, M. Fromm, A. Chambaudet

Robert Katz Publications

Unanticipated late effects in neutron and heavy ion therapy, not attributable to overdose, imply a qualitative difference between low and high LET therapy. We identify that difference as ‘ion kill’, associated with the spectrum of z/β in the radiation field, whose measurement we label ‘ion-kill dosimetry’.

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Annealed Disorder, Rare Regions, And Local Moments: A Novel Mechanism For Metal-Insulator Transitions, Dietrich Belitz, Theodore R. Kirkpatrick, Thomas Vojta May 2000

Annealed Disorder, Rare Regions, And Local Moments: A Novel Mechanism For Metal-Insulator Transitions, Dietrich Belitz, Theodore R. Kirkpatrick, Thomas Vojta

Physics Faculty Research & Creative Works

It is shown that, for noninteracting electron systems, annealed magnetic disorder leads to a new mechanism, and a new universality class, for a metal-insulator transition. The transition is driven by a vanishing of the thermodynamic density susceptibility rather than by localization effects. The critical behavior in d = 2 + ∈ dimensions is determined, and the underlying physics is discussed. It is further argued that annealed magnetic disorder, in addition to underlying quenched disorder, describes local magnetic moments in electronic systems.

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Genuine Saddle Point And Nucleation Potential For Binary Systems, Jinsong Li, Igor L. Maksimov, Gerald Wilemski May 2000

Genuine Saddle Point And Nucleation Potential For Binary Systems, Jinsong Li, Igor L. Maksimov, Gerald Wilemski

Physics Faculty Research & Creative Works

A generalized nucleation potential is constructed for binary systems. The potential consists of the reversible work of cluster formation plus additional terms arising from various kinetic effects. We show that the major nucleation flux passes through the saddle point (termed the genuine saddle point) of this generalized nucleation potential. The generalized nucleation potential reduces to the kinetic potential of a unary system when one component vanishes. The genuine saddle point concept provides a convenient way to identify systems and conditions for which the ridge crossing phenomenon occurs. Our theory agrees approximately with exact numerical results.

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Structural And Magnetic Properties Of Mechanically Milled Smco5:C, E. M. Kirkpatrick, Diandra Leslie-Pelecky May 2000

Structural And Magnetic Properties Of Mechanically Milled Smco5:C, E. M. Kirkpatrick, Diandra Leslie-Pelecky

Diandra Leslie-Pelecky Publications

Mechanically milling SmCo5 powder significantly increases coercivity and remanence ratio by introducing defects; however, these defects can be removed by room-temperature aging, with a resultant decrease in coercivity. A series of (SmCo5) x:C1–x (0.15 ≤ x ≤1) samples has been fabricated to investigate the effect of C on oxidation protection and magnetic properties. SmCo5 was premilled for 1 h, then added to C powder and milled for times ranging from 15 min to 7 h. X-ray diffraction indicates the presence of crystalline graphite and SmCo5 for milling times ≤ 6 h and also …

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Nanostructure And Magnetic Properties Of Composite Copt:C Films, M. Yu, Yi Liu, David J. Sellmyer May 2000

Nanostructure And Magnetic Properties Of Composite Copt:C Films, M. Yu, Yi Liu, David J. Sellmyer

David Sellmyer Publications

The nanostructure and magnetic properties of composite CoPt:C films at room temperature were investigated as a function of annealing temperature, carbon concentration, and film thickness. CoPt:C films with a variety of carbon concentrations were fabricated by cosputtering Co, Pt, and C onto water-cooled Si(100) substrates followed by annealing. X-ray diffraction and transmission electron microscopy analyses indicate that nanocrystallites of face-centered-tetragonal (fct) CoPt phase, which has a uniaxial magnetocrystalline anisotropy constant of about 5×107 erg/cm3, can be formed in carbon matrix when the annealing temperature is higher than 600 °C. The grain sizes of the fct CoPt crystallites …

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Magnetic And Structural Properties Of Smco7-XCuX Alloys, I.A. Al-Omari, Y. Yeshurun, Jian Zhou, David J. Sellmyer May 2000

Magnetic And Structural Properties Of Smco7-XCuX Alloys, I.A. Al-Omari, Y. Yeshurun, Jian Zhou, David J. Sellmyer

David Sellmyer Publications

We report the structural and magnetic properties of SmCo7-xCux, where x= 0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.7. X-ray diffraction shows that these alloys from the disordered hexagonal TbCu7-type structure. For large values of x (x≥0.8) the hexagonal TbCu7-type structure cannot be formed. X-ray diffraction on magnetically aligned samples show that these samples have uniaxial anisotropy. The lattice parameters (a and c) are dependent on the Cu concentration, and the unit cell volume is found to increase with x. The saturation magnetization decreases with x …

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