bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetization Changes and Losses in Conducting Ferromagnetic Materials
Authors: Becker J. J. 
Published: April 2005

This paper discusses magnetization changes and the losses associated with them in bulk metallic magnetic materials, whose behavior is determined by eddy currents. The various reversal mechanisms in these materials, the conditions under which each is operative, the losses associated with each, and the dependence of the behavior on various parameters are discussed.
The eddy-current-limited motion of an isolated domain wall is first considered. The behavior in increasingly large fields and the transition to a collapsing cylindrical or double planar wall in high fields are examined. The hysteresis loops and losses calculated for the isolated wall, the collapsing cylindrical wall, and the double planar wall are discussed for various conditions of excitation. The effects brought about in the low-frequency case by the presence of more than one wall are described, reviewing the results of theoretical calculations for multiple-wall configurations and the experimental results obtained with the superposed-high-frequency technique. The predictions of classical eddy-current theory and the ``eddy-current anomaly'' are discussed. The importance of selecting the correct model for the circumstances is illustrated by some data from the literature.
Magnetic Structure Investigations at the Nuclear Center
Authors: Ballestracci R. , Bertaut E. F. , Coing-Boyat J. , Delapalme A. , James W. , Lemaire R. , Pauthenet R. , Roult G. 
Published: April 2005

The magnetic structure of the compounds UOS, β-CoSO4, YCo5, and HoCo5 is briefly described.
UOS is antiferromagnetic. The Néel temperature is Tn=55°K. The magnetic cell is doubled in the c direction with a ++−− sequence of U moments along c. The apparent spin is S∼1. The negative interaction corresponds to U-O-U links.
In β-CoSO4 (high-temperature modification, space group Pbnm), Co atoms are in 000, 00½, ½½½, ½½0. Here three different antiferromagnetic spin modes, mutually perpendicular, Ax(+−−+), Gy(+−+−), and Cz(++−−), in the Wollan-Koehler notation, are coupled. Direction cosines are 0.71, 0.50, and 0.50, respectively. The Co moment is about 3,84 μB at 4.2°K. A field-induced spin flip to the configuration Fx, Cy, Gz is predicted.
YCO5 is ferromagnetic at room temperature with a moment value of Co practically equal to that of metallic Co and moment direction along c, which is conserved down to 4.2°K.
In HoCo5 the moment of Ho is opposite to those of the Co atoms. When cooling from room to liquid helium temperature, the direction of easy magnetization changes from near c to a direction in the basal plane and the Ho moment increases from 4 to about 9 μB. The compensation temperature is 70°K.
Structural and Magnetic Characteristics of Dysprosium-Yttrium Solid Solutions
Authors: Weinstein S. , Craig R. S. , Wallace W. E. 
Published: April 2005

X-ray studies have shown that dysprosium and yttrium are miscible in all proportions in the solid state at room temperature. Vegard's law is approximately obeyed.
Thermomagnetic analyses were carried out between 4°K and room temperature and the field dependencies were measured at liquid He, liquid N2, and room temperature on alloys containing from 10 to 95 at.% Dy. Alloys containing less than 90 at.% Dy are paramagnetic at room temperature and antiferromagnetic at lower temperatures with no clear evidence of ferromagnetism down to liquid He temperatures. The Néel point (TN) decreases with decreasing Dy content, TN32 varying linearly with composition.
Alloys containing 90 and 95 at.% Dy are ferromagnetic at low temperatures. When the samples were cooled to 4°K in the absence of a field and the magnetization measured as the sample warmed up in a field, it was observed that the moment was initially low as if the sample were antiferromagnetic (or at least nonferromagnetic). With increasing temperature the moment rose sharply to a broad maximum at about 30°K. This was followed by the appearance of Curie and Néel points. When the sample was cooled in the presence of a field, the decreased moment at low temperatures was not observed.
Magnetic Characteristics of Laves Phases Containing Lanthanide Metals Combined with Nickel
Authors: Skrabek E. A. , Wallace W. E. 
Published: April 2005

Studies have been made of the series of compounds represented by the formula ANi2, in which A is Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu. These compounds are all isostructural, possessing the MgCu2 structure. Nine of the compounds exhibit magnetic ordering at temperatures ranging from 8°K (for PrNi2) to 90°K (for GdNi2). The Y, Ce, and Lu ramain paramagnetic down to liquid helium temperatures. YNi2 and LuNi2 exhibit Pauli paramagnetism from 4° to 300°K suggesting that nickel has a filled 3d shell and is not carrying a moment in these phases. CeNi2 likewise exhibits Pauli paramagnetism, which implies that Ce has been ionized to the quadripositive state.
The measured saturation moment extrapolated to 0°K is in good agreement with the value expected if nickel is nonmagnetic and the lanthanide component carries the moment of the free tripositive ion in the case of GdNi2 but is in poor agreement for the eight other compounds which order magnetically. For all except SmNi2, which appears to be a special case, the observed moment is less than that of the free ion, the discrepancy ranging from 78% for PrNi2 to 28% for HoNi2. The low moment is attributed to the quenching effect of the crystal field, but the possibility cannot be excluded that these are not simple ferromagnets.
The moment for SmNi2 is 6.3 μB, as compared with 0.71 μB for the ground state free tripositive ion (L-S coupling). The origin of the high moment for this compound is not understood. Its magnitude can be rationalized in terms of a change to L+S coupling.
Ion Bombardment of Silicon
Authors: Primak W. , Dayal Y. , Edwards E. 
Published: April 2005

When silicon plates were bombarded with protons of energies about 100 kV, the infrared absorption spectrum above 1.1 μ showed chromatic fringes corresponding approximately to the range of the protons. The fringes did not begin to disappear on annealing until the plates were heated to over 1100°C. The effect appears to be caused by a reflecting layer involving trapped hydrogen. After long irradiation, small flatbottomed pits were found of about the depth of the range.
The effect could also be produced with helium ions on silicon. No effect was found with germanium.
Ion Bombardment of Single Crystals of Aluminum
Authors: Cunningham R. L. , Gow K. V. , Ng-Yelim Joyce 
Published: April 2005

This paper presents the results of bombarding the (100), (110), and (111) surfaces of aluminum single crystals with a narrow beam of 8-kV argon ions. The crystals were tilted at the angles required to bring [110], [100], [112], and [111] directions parallel to the beam. The experiments were designed to study the effect of incident ion direction on ejection directions and etching rates.
Ejection directions, as determined from the positions of deposits on hemispherical collectors, were found to be independent of incident ion direction for a given surface orientation. The quantity of material ejected along equivalent ejection directions was observed to decrease as the angle of deviation between the incident ion beam and the ejection direction increased. The principal ejection directions observed were [110]. Apparent [116] ejection directions were observed when (110) and (111) surfaces were bombarded. These were caused by an abrupt deflection of momentum from [110] directions of the crystal to directions close to [110] of elementary twins. These are formed by surface atoms in twin positions on (111) surfaces developed, in the case of the (110) surface, during bombardment. The [110] directions of an elementary twin are parallel to certain [114] directions of the crystal, and, had multilayer twins been formed, the resulting ejection would have been along apparent [114] directions as a result of Silsbee focusing. Ejection along apparent [116] directions was not observed from (100) surfaces presumably because predominant [100] surface grooves produced by bombardment could not contain (111) facets. Under these conditions [100] ejection was detected.
Etching rates, as judged by the occurrence of matte spots, were least when the beam was parallel to the close-packed [110] directions and greatest when parallel to high index directions making large angles with the [110] directions. Low etching rates were also observed when the beam became parallel to [100] and [112] directions. Any anisotropy in surface migration rates was shown to be negligible in controlling etching rates under the conditions of these experiments.
Conductivity of a Medium Containing a Dense Array of Perfectly Conducting Spheres or Cylinders or Nonconducting Cylinders
Authors: Keller Joseph B. 
Published: April 2005

The effective electrical conductivity σ is computed for a composite medium consisting of a dense cubic array of identical, perfectly conducting spheres imbedded in a medium of conductivity σ0. When f, the fractional volume occupied by the spheres, is near its maximum value π/6, the result is σ/σ0=−(π/2)log [(π/6)−f]+…,(π/6)−f≪1. This result exhibits the singularity of σ at f=π/6, when the spheres touch each other. The previous results of Maxwell, of Rayleigh and of Meredith and Tobias are not valid near the singularity and they fail to reveal it. For f=0.5161 our result yields σ/σ0=7.65, while the measurement of Meredith and Tobias yielded σ/σ0=7.6.
For a medium containing a square array of perfectly conducting circular cylinders we obtain σ/σ0=π32/2[(π/4−f)]12+…,(π/4)−f≪1. This result agrees well with the numerical results of H. B. Keller and D. Sachs. We also prove that for any value of f, σ/σ0 for a medium containing a square array of nonconducting cylinders is the reciprocal of σ/σ0 for the same array of perfectly conducting cylinders.
Average Neutron Energy of Reactor Spectra and Its Influence on Displacement Damage
Authors: Kantz A. D. 
Published: April 2005

The average energy of the neutron spectrum for reactor sources may be evaluated to good approximation by a threshold-reaction technique using the activation of only two threshold-reaction foils. For plutonium (effective threshold 0.001 MeV) and sulfur (effective threshold 3.0 MeV) foils the average energy of a reactor spectrum is found to be Ē=7.42R+0.30 MeV, where R is the ratio of the number flux measured above the sulfur threshold to the number flux measured above the plutonium threshold.
The carrier removal rate per unit flux has been measured for vacuum floating zone n-type silicon (phosphorus-doped) as a function of the average energy of the reactor spectrum as measured by the two-foil method. Resistivities of 1-, 10-, and 100-Ω-cm samples were used in these irradiations at seven different reactor spectra. The carrier removal rate is found to be proportional to the average energy of the neutron spectrum. The highest average energy realized in the experimental work was 2.3 MeV.
Equation of State of 6061-T6 Aluminum at Low Pressures
Authors: Lundergan C. D. , Herrmann Walter 
Published: April 2005

The Hugoniot equation of state of 6061-T6 aluminum was determined in the pressure range from 0 to 31 kbars from measurements of velocities of plane waves induced by plate impact. Below the Hugoniot yield point of 6.4±0.7 kbars, only an elastic wave was observed, while above both elastic and plastic waves were observed. The measured wave velocities corresponded closely to values predicted from elastic parameters for the material determined in static tests. Above the elastic limit, the free-surface velocity was less than the interface velocity by an amount slightly greater than predicted by theory, and appeared to be a function of target thickness.
The measured Hugoniot was found to correspond well with elementary elastic-plastic theory, in which the yield stress is assumed to be a constant, and the change in compressibility with compression is predicted by second order elastic theory. It was found that the measured Hugoniot yield stress corresponded to the static yield stress obtained in simple tension tests, and that the Hugoniot joined smoothly onto an extrapolation of the high pressure Hugoniot data of Walsh and Al'Tshuler.
Photocontrol of Growth Rate of Thin Polymer Films Formed by Electron Bombardment
Authors: Mayer Ludwig 
Published: April 2005

This paper reports on an exploratory study concerned with the formation of thin polymer films on metal film substrates bombarded by slow electrons. The essential results of the investigation are: Cracking, polymerization, and crosslinking of organic molecules adsorbed on surfaces by electron bombardment can be achieved with electron energies as low as 6 eV. The formation rate of thin polymer films in the low electron region is voltage-dependent. Polymer films formed from organic molecules inherently present in a high vacuum system show electrical photoresponse in the visible and near-infrared region of the spectrum. By utilizing this photoresponse and the voltage dependence of the film growth rate, polymer film configurations can be grown which correspond to light patterns projected onto them.
All experiments were conducted in an electron mirror microscope which proved to ideally suited for this type of study. Such a microscope is a very sensitive tool for the detection and observation of extremely thin insulating films. It permits formation of thin polymer films in an easy fashion and it serves equally well as a convenient instrument for immediate detection and study of such films during growth. The transition from growing polymer films to observing them can be accomplished simply by switching the bias potential on the polymer film's conductive substrate.
In one example, illustrated by an electron mirror micrograph, the experimental procedures are described in detail.
Magnetic Properties of the Dual Oxide System CuO–Fe2O3
Authors: Milligan W. O. , Tamai Y. , Richardson J. T. 
Published: April 2005

It has been demonstrated that hydrous ferric oxide and cupric oxide gels consist of very small particles and contain magnetically dilute Fe3+ and Cu2+ ions, respectively. Heating or aging these gels produces an increase in particle size with the onset of crystalline magnetic interactions. Coprecipitated samples of these oxides contain no CuFe2O4 when merely air-dried or heated at 170°C, but consist of mixtures of CuO and α-Fe2O3.
Higher heat-treatment of these samples up to 900°C results in mixtures of CuFe2O4 and/or α-Fe2O3 and CuO, with the amount of CuFe2O4 increasing with temperature of heat-treatment. Heat-treatment at 1100°C produces a solid solution of CuF2O4 and γ-Fe2O3 in the range greater than 40 mole % Fe2O3. Analysis of the ferrimagnetic magnetization and Curie points suggest that γ-Fe2O3 has a Curie point of 625°C and a magnetization of 65.0 emu/g. The results are consistent with cationic distribution of Fe[Fe5/3□1/3]O4 and Fe[CuFe]O4.
Calculation of Fields, Forces, and Mutual Inductances of Current Systems by Elliptic Integrals
Authors: Garrett Milan Wayne 
Published: April 2005

A minimum-ordered set of elliptic integral equations is given for magnetic vector potential, axial and radial fields, the mixed gradient ∂Bρ/∂z for axially symmetric iron-free current systems, and for mutual inductance and force between coaxial units. The units may be circular loops, cylindrical or plane annular current sheets, or coils of thick section. With full use of correlations, six basic equations suffice for all properties of loops, solenoids, or combinations. The axial solenoid field is calculated by a superior new method. Thick coils are analyzed with the solenoid rather than the loop as element. Magnetic properties are then integrated in radial depth by Gaussian numerical quadrature of variable order. This method can deal with coils whose sections are not rectangular, and whose current densities are a function of the cylindrical radius.
No tables are used, and the procedure is simpler and faster than previous methods, for computer use or for solving smaller problems by hand. It has been coded as a unified set of programs for the IBM 7090. These will be described elsewhere; they can compute fields, and trace lines of force even within the windings, or force and mutual inductance between coils in contact, also self-inductance of ideal solenoids or of thick cylindrical coils. Errors are normally less than one part per million, in extreme cases less than one per thousand.
On Strain-Enhanced Diffusion in Metals. III. Interpretation of Recent Experiments
Authors: Ruoff A. L. , Balluffi R. W. 
Published: April 2005

A critical interpretation of recent experimental results on the effects of plastic deformation on diffusion is carried out with the aid of the results established in the preceding Parts I and II. Attention is focused on experiments carried out at elevated temperatures (higher than half the absolute melting temperature) in which diffusion occurred over macroscopic distances. The results are discussed in terms of the following possible causes of apparent enhanced diffusion: (1) generation and migration of excess point defects during deformation; (2) short-circuiting along static or moving dislocations or grain boundaries created in the deformation; (3) short-circuiting along cracks created in the deformation; and (4) experimental difficulties associated with interface roughness. Causes (3) and (4) are of little basic interest but must be considered in any survey of experimental results.
Fourteen experiments in all are considered. Ten of these experiments showed no apparent enhancements within the expected experimental error of about 50% in the diffusivity. In one of these ten experiments a large enhancement was reported, but is is shown that this was due solely to an error in mathematical analysis.
Two of the experiments showed large apparent enhancements, and it is shown that they were almost certainly due to (4). One of the experiments showed apparent enhancements due to (3) but showed no enhancement in the absence of cracking. One of the experiments showed enhancements which, it is concluded, are not inconsistent with present knowledge of (2). [Very recent work by Brown and Blackburn (unpublished) indicate that at least some of the enhancements in this experiment may have been due to (4)].
It is generally concluded that in no case has a diffusion enhancement been detected due to the generation of excess vacancies. However, enhancement in one case may have occurred as a result of short-circuiting. These results are consistent with other high temperature deformation phenomena, e.g., creep kinetics, and are also consistent with the point defect and short-circuiting models developed in the preceding Parts I and II which predict very small effects due to point defects and possibly larger effects in certain cases due to short-circuiting.
Effects of a Guardring upon Low-Energy Sputtering Yields of Flat, Single-Crystal Gold Targets
Authors: Kreye W. C. 
Published: April 2005

Spectrometric sputtering yield measurements were performed upon flat, single-crystal gold targets in a supported argon plasma, and the results are compared with those obtained when a large copper guardring was placed about the target. After the results are adjusted to similar discharge conditions, the relative yields without the guardring are greater for all three orientations, (100), (110), and (111). The increase is attributed to the formation of a curvature to the Langmuir layer immediately about the gold target when the guardring is not used. This introduces ions which strike the gold surface at oblique incidence angles.
The square root of the relative yield is plotted against the target voltage, and the curves are found to be linear in the range of 40–70 V. The intercepts EE of the extrapolated linear portions of the two curves, with and without a guardring, are found to be equal for each orientation. These values, at 9 μ of argon, are 33, 28.5, and 35 eV for the (100), (110), and (111) faces, respectively. These values do not include the subtractive correction for the plasma potential whose measured value is approximately 15 eV.
For the (100) and (111) faces, the calculated differences [EE−EE(110)] are proportional to the corresponding differences in the binding energies of a surface atom which is in an upper, complete lattice plane.
Self-Diffusion in Silver during Plastic Deformation in Extension and Compression
Authors: Darby J. B. , Tomizuka C. T. , Balluffi R. W. 
Published: April 2005

Self-diffusion of Ag110 in silver single crystals subjected to simultaneous deformation at 800 and 900°C was studied using the sectioning technique. The crystals were orientated for duplex slip and were deformed in extension and compression at constant strain rates in the range 1 to 28×10−5 sec.−1. Total strains as large as 0.33 were attained. Recrystallization occurred in the initially single crystal specimens during diffusion-deformation under all conditions except tension at 800°C.
The effect of straining on the rate of diffusion was found to be small in all cases. The straining changed the diffusivities by less than 50%, and it is concluded that the observed changes were probably within the experimental error. The results indicate that any increases in diffusion rate due to the generation of point defects or short-circuiting paths during deformation were small. These conclusions are shown to be consistent with other experiments involving these phenomena.
Inelastic Ion-Atom Collisions
Authors: Hasted J. B. 
Published: April 2005

Ion-atom charge exchange cross sections of incident ion velocity v in the adiabatic region are shown to be proportional to exp (−K′a|ΔE|/v) energy defect ΔE.
Maximum cross sections of the negative ion-atom detachment collision and certain other inelastic ion-atom collisions are shown to be proportional to the maximum kinetic energy available for internal excitation, ½μv2, where μ is the reduced mass of the system. The semiempirical prediction of cross-section energy dependence is discussed.
On Model Studies of Metallic Surface Asperities
Authors: Ling F. F. , Lucek R. C. 
Published: April 2005

An apparatus for measuring forces generated at the tips of two cones throughout the sliding-contact life cycle is described. The cones are used to simulate surface asperities. Test results under atmospheric conditions show the following: (1) For cones with 90° internal angles, the ratio of the integrated value of the horizontal force component over the length of the life cycle to that of the vertical force component, a measure of coefficient of friction after Green, is not sensitive to the presence of lubricants in cases where the cone tips are in line or nearly in line with the direction of relative motion; but the ratio is substantially lowered in the presence of lubricants when the cone tips are far from being in line with the direction of relative motion. The former cases are always accompanied by the formation of macroscopic wear debris. (2) By increasing the internal angle of cones, the ratio defined above is decreased, but its value does not seem to approach zero for the angle approaching 180°, a flat surface. (3) Size effect as discussed by Morrison and Shaw is evidenced in this experiment.
The mutual inclusiveness of the classical interlock theory and the popular adhesion theory of friction is discussed. Moreover, the coefficient of friction for a pair of idealized surfaces with asperities in the form of 90° cones and randomly distributed is calculated from considerable amount of test data. While actual surfaces have asperities roughly in the form of cones with internal angles much larger than 90°, right circular cones were used, nevertheless, for simplicity and for amplifying the effects noted.