bluuebunny/crossref_metadata_2025 huggingface dataset:
RISK FACTORS DIFFER ACCORDING TO SAME-SEX AND OPPOSITE-SEX INTEREST
Authors: RICHARD UDRY J. , CHANTALA KIM
Published: June 2005

Are risk behaviours in adolescence differentiated according to same-sex vs opposite-sex interest? For all respondents a five-point scale of interest in each sex used information from both of the first two in-home waves of the National Longitudinal Study of Adolescent Health (Add Health). Logistic regression predicted the probability of experiencing each risk behaviour from the same-sex and opposite-sex interest scores. Same-sex interests have more effect on emotional risk, and opposite-sex interests have more effect on substance use. Nevertheless, all risk variables except boys’ depression are responsive to both same-sex and opposite-sex interest. The same-sex interest component of risk is attributed to the emotional strain of living with an anomalous sex interest in a heterosexual society.
SIGNIFICANT EFFECTS OF BIRTH-RELATED BIOLOGICAL FACTORS ON PRE-ADOLESCENT NUTRITIONAL STATUS AMONG RURAL SUNDANESE IN WEST JAVA, INDONESIA
Authors: SEKIYAMA MAKIKO , OHTSUKA RYUTARO
Published: June 2005

The Sundanese inhabiting West Java, the second largest ethnic group in Indonesia, are characterized by a high prevalence of child malnutrition, together with high fertility. Based on an anthropometric measurement and interview survey of 310 children aged 5–12 years in a rural Sundanese village, this study examined the relative significance of the effects of eight biological, eight socioeconomic status (SES) and four health behavioural factors on their Z scores for height-for-age (HAZ) and weight-for-age (WAZ) in particular. Three biological factors, i.e. birth interval, birth weight and mother’s body weight, and one SES factor, i.e. mother’s occupation, were selected as the predictors of the two Z scores by regression analysis, indicating more significant effects of the biological factors than the other factors. This pattern is judged to occur in less-developed and high-fertility populations. Since these two Z scores were worse in the subject children than in the under-5-year-old children from the same village, more attention should be paid to the long-lasting effects of birth-related biological factors up to pre-adolescent ages, as an insufficient nutritional status tends to damage growth and health in adolescence and adulthood.
STERILIZATION AND UNION INSTABILITY IN BRAZIL
Authors: LEONE TIZIANA , HINDE ANDREW
Published: June 2005

Brazilian women rely on sterilization as the main source of birth control. Sterilization has been one of the causes of the steep decline in fertility in Brazil, at least since the second half of 1970. It is hypothesized that understanding couples’ relationships might be key to explaining this high rate of female sterilizations. Possible reasons for the higher level of fertility among women in unstable unions than among women in stable ones could be the less effective use of contraceptive methods, or that women in unstable unions tend to use less effective or reversible contraceptive methods. In this paper discrete time modelling of the timing of sterilization according to union histories is presented. The analysis uses the calendar data of the 1996 Brazilian DHS. It is shown that women in second or higher order unions have a lower risk of sterilization. This result should be taken into account in the analysis of the determinants of female sterilization in Brazil.
Conservation outside of parks: attitudes of local people in Laikipia, Kenya
Authors: GADD MICHELLE E.
Published: June 2005

Conflict between wildlife and people can erode local support for conservation. Wildlife-based benefits are intended to offset costs and encourage tolerance or stewardship, but where the linkage between benefits and wildlife is not understood, benefits may be ineffective at bolstering conservation. In Laikipia, Kenya, wildlife and areas devoted to wildlife are on the increase, but most residents still suffer losses to wildlife and derive minimal benefits. The elephant situation is particularly problematic because elephants may compete with livestock for resources, raid people's crops, and chase and kill livestock and people. Although most unprotected elephant range in East Africa is in semi-arid rangelands occupied by pastoralists, previous research has emphasized agricultural, not pastoral or agri-pastoral conflicts. Between 1999 and 2002, interviews were conducted in Laikipia District to examine whether pastoralists also experience conflict, and to determine whether wildlife conservation provided appreciable benefits to residents, or fostered pro-conservation attitudes among residents. Three properties, Endana, Koija and Mpala, were selected to include the two primary land uses in Laikipia (livestock and agriculture) and two levels of wildlife-based benefits (indirect benefits and direct benefits from a locally-owned tourism operation). People were negative about many aspects of local wildlife conservation, especially animals that raided crops or were dangerous. Fundamental differences in attitudes were attributable to primary land use; within ethnic groups, people practising agriculture were less tolerant of elephants than people practising pastoralism. Despite evidence that elephants may compete with livestock for forage, ecological competition was not a primary concern among cattle-keeping people. In communities that received indirect benefits from tourism or wildlife, the connection between wildlife and employment or aid in kind was usually overlooked. Unlike elsewhere in Africa, education and wealth did not correlate with positive attitudes towards wildlife because the tourism programme was improving the situation and the outlook of people lacking education and material wealth. Pastoral people with indirect financial benefits expressed positive attitudes towards elephants for aesthetic reasons, while pastoral people with direct benefits cited financial rewards derived from tourism but attributed aesthetic values to living with elephants. The programme in the pastoral community receiving benefits was exemplary in that benefits were tangible, and the participants appreciated the linkage between benefits and active conservation. Land conversion from pastoralism to agriculture threatens elephant survival, not only in terms of habitat loss, but also in terms of lost tolerance among people who have shifted to farming.
Ab initio kinetics of the reaction of HCO with NO: Abstraction versus association/elimination mechanism
Authors: Xu Z. F. , Hsu C.-H. , Lin M. C.
Published: June 2005

The kinetics and mechanism for the reaction of HCO with NO occurring by both singlet and triplet electronic state potential-energy surfaces (PESs) have been studied at the modified Gaussian-2 level of theory based on the geometric parameters optimized by the Becke-3 Lee–Yang–Parr/6-311G(d,p) method. There are two major reaction channels on both singlet and triplet PESs studied: one is direct H abstraction producing CO+HNO and the other is association forming a stable HC(O)NO (nitrosoformaldehyde) molecule. The dominant reaction is predicted to be the direct H abstraction occurring primarily by the lowest-energy path via a loose hydrogen-bonding singlet molecular complex, ON⋯HCO, with a 2.9-kcal/mol binding energy and a small decomposition barrier (1.9 kcal/mol). The commonly assumed HC(O)NO intermediate, predicted to lie below the reactants by 27.7 kcal/mol, has a high HNO-elimination barrier (34.5 kcal/mol). Bimolecular rate constants for the formation of the singlet products and their branching ratios have been calculated in the temperature range of 200–3000 K. The rate constant for the disproportionation process producing HNO+CO, found to be affected strongly by multiple reflections above the well of the complex at low temperature, is predicted to be k(HNO)=3.08×10−12T0.10exp(242∕T) for 200–500 K, and 1.72×10−16T1.47exp(888∕T) for 500–3000 K in units of cm3molecule−1s−1. The high- and low-pressure rate constants for the association process forming HC(O)NO can be represented by k∞=4.42×10−11T0.25exp(−28∕T) cm3molecule−1s−1 (200–3000 K) and k0=7.30×10−16T−5.75exp(−719∕T) (200–1000 K) and 1.82×102T−11.92exp(1846∕T) (1000–3000 K) cm6molecule−2s−1 for N2-buffer gas. The absolute values of total rate constant, predicted to be weakly dependent negatively on temperature but positively on pressure, are in close agreement with most experimental data within their reported errors.
Separation of gas mixtures using a range of zeolite membranes: A molecular-dynamics study
Authors: Jia W. , Murad S.
Published: June 2005

Gas separation efficiencies of three zeolite membranes (Faujasite, MFI, and Chabazite) have been examined using the method of molecular dynamics. Our investigation has allowed us to study the effects of pore size and structure, state conditions, and compositions on the permeation of two binary gas mixtures, O2∕N2 and CO2∕N2. We have found that for the mixture components with similar sizes and adsorption characteristics, such as O2∕N2, small-pore zeolites are not suited for separations, and this result is explicable at the molecular level. For mixture components with differing adsorption behavior, such as CO2∕N2, separation is mainly governed by adsorption and small-pore zeolites separate such gases quite efficiently. When selective adsorption takes place, we have found that, for species with low adsorption, the permeation rate is low, even if the diffusion rate is quite high. Our results further indicate that loading (adsorption) dominates the separation of gas mixtures in small-pore zeolites, such as MFI and Chabazite. For larger-pore zeolites such as Faujasite, diffusion rates do have some effect on gas mixture separation, although adsorption continues to be important. Finally, our simulations using existing intermolecular potential models have replicated all known experimental results for these systems. This shows that molecular simulations could serve as a useful screening tool to determine the suitability of a membrane for potential separation applications.
Traps in germanium nanocrystal memory and effect on charge retention: Modeling and experimental measurements
Authors: Koh B. H. , Kan E. W. H. , Chim W. K. , Choi W. K. , Antoniadis D. A. , Fitzgerald E. A.
Published: June 2005

Surface traps, or traps at the interface of the nanocrystal and the surrounding matrix, play an important role in the charge retention performance of nanocrystal memory transistors. In this article, we report the investigation of trap energy levels in nanocrystalline germanium (nc-Ge) memory transistor and capacitor structures and their effect on the device charging and discharging kinetics through theoretical modeling and experimental measurements. The theoretical model, calibrated using the experimental data, uses a self-consistent quantum-mechanical tunneling numerical approach for calculating the transmission coefficient across the tunnel barrier. The effect of the trap energy on charge retention is shown by temperature-dependent measurements on the nc-Ge memory structures. The trap energy-level requirement for achieving a specified long-term charge retention performance (i.e., 10-yr retention time) is obtained from simulation as a function of the nanocrystal size.
Low-temperature metallic behavior of amorphous MoO3–TeO2 thin films
Authors: Mukherjee Soma. , Karmakar S. , Sakata H. , Chaudhuri B. K.
Published: June 2005

We report that vacuum-deposited amorphous MoO3–TeO2 films of different thickness (469–1185 nm) and compositions show metal-insulator transition (MIT) in the temperature (Tp) range 341–231 K (depending on thickness and composition). Interestingly, the corresponding thick bulk glass plates (∼0.2–0.5-mm thickness) of same compositions behave like the usual semiconducting transition metal oxide glasses over the entire range of temperature (80–400 K) and follow small polaron hopping (SPH) conduction mechanism. Temperature-dependent resistivity curves of the films showed peaks (maxima) around the respective MIT temperature Tp, which shifted to the lower-temperature region with the increase of MoO3 content. Fitting of the conductivity data of the film in the high-temperature (T>Tp) semiconducting phase shows a crossover around Tc(>Tp) from the Mott variable range hopping to SPH behavior, which is in sharp contrast to the behavior of the bulk glass. In these films, the estimated localization length (ξ) diverges as MIT is approached from the high-temperature phase. Low-temperature (T<Tp) magnetic-field-independent metallic part of the resistivity (ρ) data of higher (⩾60%)TeO2 containing films can be fitted with ρ=ρ0+ρ2T2 indicating the importance of electron-electron scattering (second term) mechanism of conduction. The corresponding metallic behavior of the comparatively high-resistive and lower (⩽50%)TeO2 containing film is, however, more complicated. All these different features of these glassy films suggest that their glass network structure is different from that of the corresponding bulk glass (indicating a change of glass network structure in the film phase), which is considered to be responsible for the metallic transition in the films.
Electron energy-dependent product state distributions in the dissociative recombination of O2+
Authors: Petrignani Annemieke , Hellberg Fredrik , Thomas Richard D. , Larsson Mats , Cosby Philip C. , van der Zande Wim J.
Published: June 2005

We present product state distributions and quantum yields from the dissociative recombination reaction of O2+ in its electronic and vibrational ground states as a function of electron collision energy between 0 and 300meV. The experiments have been performed in the heavy-ion storage ring, CRYRING, and use a cold hollow-cathode discharge source for the production of cold molecular oxygen ions. The branching fractions over the different dissociation limits show distinct oscillations while the resulting product quantum yields are largely independent of electron collision energy above 40meV. The branching results are well reproduced assuming an isotropic dissociation process, in contrast with recent theoretical predictions.
Local superfield Lagrangian BRST quantization
Authors: Gitman D. M. , Moshin P. Yu. , Reshetnyak A. A.
Published: June 2005

A θ-local formulation of superfield Lagrangian quantization in non-Abelian hypergauges is proposed on the basis of an extension of general reducible gauge theories to special superfield models with a Grassmann parameter θ. We solve the problem of describing the quantum action and the gauge algebra of an L-stage-reducible superfield model in terms of a BRST charge for a formal dynamical system with first-class constraints of (L+1)-stage reducibility. Starting from θ-local functions of the quantum and gauge-fixing actions, with an essential use of Darboux coordinates on the antisymplectic manifold, we construct a superfield generating functionals of Green’s functions, including the effective action. We present two superfield forms of BRST transformations, considered as θ-shifts along vector fields defined by Hamiltonian-like systems constructed in terms of the quantum and gauge-fixing actions and an arbitrary θ-local boson function, as well as in terms of corresponding fermion functionals, through Poisson brackets with opposite Grassmann parities. The gauge independence of the S-matrix is proved. The Ward identities are derived. Connection is established with the BV method, the multilevel Batalin-Tyutin formalism, as well as with the superfield quantization scheme of Lavrov, Moshin, and Reshetnyak, extended to the case of general coordinates.
Phase dependence of electron acceleration in a tightly focused laser beam
Authors: He Xinkui , Li R. X. , Shuai B. , Ge X. C. , Xu Z. Z.
Published: June 2005

Electron acceleration using a tightly focused ultraintensity laser beam is investigated numerically and strong phase dependence is found. The acceleration is periodic to the variety of the initial laser field phase, and the accelerated electrons are emitted in pulses of which the full width is the half period of the laser field. When a 10 PW intense laser beam is used, the electron with energy less than 1 Mev can be accelerated up to energies about 1.4 GeV. The optimal initial condition for electron acceleration is found.
Covariant kinetic dispersion theory of linear waves in anisotropic plasmas. III. Counterstreaming plasmas
Authors: Tautz R. C. , Schlickeiser R.
Published: June 2005

The properties of longitudinal and transverse oscillations in unmagnetized counterstreaming Maxwellian plasmas of arbitrary composition for waves propagating parallel to the stream direction are investigated on the basis of Maxwell equations and the relativistic Vlasov equation. These dispersion relations describe the linear response of the system to the initial perturbations and thus define all existing linear parallel propagating plasma modes in the system. By analytic continuation the dispersion relations in the whole complex frequency plane are constructed. The dispersion relations hold for any values of the plasma temperatures, streaming velocity, intensities of the two streams, and for all wave number and frequency values of the oscillations. In the limit of nonrelativistic plasma temperatures these general dispersion relations can be expressed in terms of the well-documented Fried and Conte plasma dispersion function. Only in the case of infinitely large speed of light they agree with the standard nonrelativistic results.
Temperature dependence of the field emission of multiwalled carbon nanotubes
Authors: Tan Cher Ming , Jia Junji , Yu Weibo
Published: June 2005

The field emission characteristics of multiwalled carbon nanotubes at various temperatures are studied. It is found that the turn-on field and emission current at a given applied electric field are dependent on the ambient temperature of the nanotube. This dependence is believed to be due to the change in the work function of the nanotube on temperature, and the dependence of the work function with temperature is calculated. The direct application of such temperature dependence is a simple and low-cost nanothermometer.
Absorption and Reflectivity Measurements on Some Rare Earth Iron Garnets and α-Fe2O3
Authors: Bailey P. C.
Published: June 2005

Measurements of the absorption coefficient of (111) crystal sections of α-Fe2O3 were made in the visible and near infrared. Absorption peaks were observed centered at energies of about 12000 cm−1 and 16000cm1. Reflectivity measurements on the α-Fe2O3 crystals were carried out in the 30000 cm−1 to 400 cm−1range. Broad reflectivity peaks are found in the near ultraviolet at 24500 cm−1 and 26000 cm−1, respectively. Very strong reflection peaks resulting from the lattice vibrations are present at energies smaller than 700 cm−1.

Several quite sharp peaks are found in the absorption spectra of the rare-earth iron garnets of Dy, Ho,Er and Yb in the 10000 cm−1–13000 cm−1 energy range. The circular dichroism of ytterbium iron garnet is displayed by means of absorption curves for the two senses of circularly polarized light.
Ferrimagnetic Resonance in Impurity Doped Yttrium Iron Garnet (YIG)
Authors: Dillon J. F. , Nielsen J. W.
Published: June 2005

A research program aimed at understanding our earlier line width and anisotropy measurements on YIG has led to a study of ferrimagnetic resonance in doped crystals. YIG crystals have been grown containing appropriate concentrations (∼.01 to 5.0 atomic percent) of various impurities, including the 4f rare earth elements, members of the iron transition group, and several non-magnetic elements. This paper gives new results for the variation of the field for resonance with crystal direction at several temperatures in the liquid hydrogen and liquid helium range. In the case of holmium, sharp peaks in the Hres vs angle curve are seen which vary rapidly with temperature. The corresponding curves for the dysprosium containing sample do not show such sharp variations in (110), and at least in part do not vary with temperature below about 4°K. Though Kittel's recent theoretical results should apparently apply to the peaks in the holmium case, his results for the temperature dependence of the anomaly height and width do not correspond with our data.
Initial Permeability Characteristics of Mixed Yttrium-Gadolinium Iron Garnets
Authors: McDuffie G. E. , Cunningham J. R. , Anderson E. E.
Published: June 2005

Complex initial permeability measurements have been made on polycrystalline garnet toroids of the form (3−x)Y2O3·xGd2O3·5Fe2O3 where x ranged from zero (yttrium iron garnet) to three (gadolinium irongarnet). Both the real initial permeability μ′ and the imaginary initial permeability μ′′ were measured at 23°C, −78°C and −196°C over a frequency range of 1 kc to 2000 Mc. At room temperature, the low frequency value of μ′ was found to decrease with increasing gadolinium content. At lower temperatures the low frequency value of μ′ exhibits a minimum in x caused by the temperature dependent behavior of the two different magnetic sublattices. The frequency at which the maximum value of μ′′ occurs was found to increase with the addition of gadolinium. No thermal relaxation was observed in these garnets, but rather the peaks in the curves shifted to slightly higher frequencies with decreasing temperature.
Paramagnetic Resonance of Yb+++ in Aluminum and Gallium Garnets
Authors: Carson John W. , White Robert L.
Published: June 2005

The paramagnetic resonance spectrum of Yb+++ in gallium and aluminum garnets has been observed at liquid nitrogen and helium temperatures. The components of the principal g tensor are 2.85, 3.60, and 3.74 in gallium garnet, and 2.47, 3.78, and 3.87 in aluminum garnet. In aluminum garnet, for a range of Yb concentrations(relative to Y) of from 2% to .1%, the line width varies linearly from 98 gauss to 20 gauss. The longitudinal relaxation time T1, for the same Yb variation, increases from 0.001 sec to 0.02 sec.
Angular Variation of the Magnetic Properties of Elongated Single-Domain Iron Particles
Authors: Luborsky F. E. , Paine T. O.
Published: June 2005

The demagnetization curves of oriented elongated single-domain (ESD) iron particles have been measured as a function of angle and packing fraction. The reduced coercive forces of dilute compacts show a maximum at an angle of about 50° associated with a buckling magnetization reversal. As the packing fraction is increased,particle magnetostatic interaction lowers the coercive force and suppresses the 50° max. The residual to saturation ratio appears as a distorted cosine function, which the simple single-domain particle model cannot account for without assuming particle orientations inconsistent with electron micrographs. A more realistic model is proposed which accounts for the experimental results by considering the effect on particle domain structure of dendritic branches and cross-links to adjacent particles. The new model has been analyzed by measuring the magnetic properties of arrays of pivoted magnets, which simulate the proposed domain configurations at various angles and packing fractions.
Hot Working of Alnico 5 Alloys
Authors: Kolbe C. L. , Martin D. L.
Published: June 2005

Alnico permanent magnet alloys have been successfully shaped into rod, wire and strip by hot working at elevated temperature. It has been found that by careful processing, certain Alnico alloys can be fabricated by extrusion, swaging, and rolling. The wrought Alnico after heat treatment was found to have comparable permanent magnet properties and improved mechanical properties compared to cast specimens of the same alloy.
Use of Magnetostatic Modes as a Research Tool
Authors: White Robert L.
Published: June 2005

The use of ferrimagnetic resonance and in particular of the magnetostatic modes of spheres to obtain information on basic physical magnetic parameters is discussed. The effects of random and systematic deviations of the experimental situation from the theoretical upon the determination of 4πM, γ, and the magnetic anisotropy constants are treated. A summary is also given of the use of line width and rf power saturation measurements on the magnetostatic modes to obtain information on the spin-wave spectrum of the material.
Anisotropic Magnetization
Authors: Callen Earl R.
Published: June 2005

In the presence of magnetocrystalline anisotropy the magnetization of a ferromagnet depends upon its orientation as well as upon the temperature. The temperature dependences of the anisotropic parts of the magnetization have been worked out, both classically and quantum-mechanically, for all symmetries and for ferro- and ferrimagnets in the internal field approximation. The nonspherical terms are small at all temperatures in iron and nickel but are appreciable in some uniaxial materials, and very large in many crystals of low Curie point and large anisotropy. In these materials the magnetization will be very unlike a Brillouin function.
Exchange Anisotropy in Rock Magnetism
Authors: Meiklejohn W. H. , Carter R. E.
Published: June 2005

Some igneous rocks are magnetized in a direction opposite to that expected, if they had been cooled in the earth's magnetic field. These rocks are said to have a reverse thermo-remanent magnetization (reverse TRM). Uyeda has shown that the reverse TRM of the Haruna deposit in Japan is due to an ilmenite-hematite solid solution and has synthesized a solid solution that has a reverse TRM when cooled in fields as high as 16000 oe. He has put forth a theory which contains a mechanism similar to that found in the cobalt-cobaltous oxide system.

Based upon Uyeda's explanation of the reverse TRM, we postulated that the material should have a shifted hysteresis loop and that it should be shifted in the opposite direction to that found in the Co-CoO system. We found that the solid solution—0.6 FeTiO3 0.4 Fe2O3—was shifted by 350 oe in the opposite direction to Co-CoO when cooled in a field. The loop was symmetrical when cooled in zero field. Moreover,we have shown that when the material is cooled in a magnetic field through the Morin transition the loop is shifted in the same direction as Co-CoO.

These results confirm the general features of Uyeda'a model, although the detailed mechanism is still being studied.

We believe that Uyeda's work definitely establishes the reverse TRM of the Haruna deposit as due to a magnetic phenomenon and not due to the reversal of the earth's magnetic field. We believe that the type of magnetic investigation reported in this paper may be applied to other deposits that have a reverse TRM to establish if they are also due to a magnetic phenomenon.
Practical Hysteresigraph
Authors: Bockemuehl R. R. , Sargeant W. E.
Published: June 2005

A relatively low-cost hysteresigraph has been developed which is suitable for both laboratory and industrial application. The instrument utilizes standard component parts and employs mutual inductance feedback to perform the necessary integrating operation. The instrument is reasonably insensitive to environment and permits direct recordings of hysteresis loops and magnetization curves to be made in less than one minute. Both theoretical and practical considerations of the instrument are presented.
Magnetic Field Measurement Using Ultrasonics
Authors: Radus R. J.
Published: June 2005

The detection and measurement of magnetic field intensity for purposes of field plotting and uniformity studies is a most important consideration in the field of magnetics. Field plotting and uniformity studies have been conducted on certain sizes of magnetic geometries with rotating coil instruments and Hall generators and quartz crystal magnetometer. The obvious limit of such devices is their minimum resolving power which can be defined in terms of sampling area and mimimum air gap. For the rotating coil instruments, the minimum air gap is 14 in. and the sampling area is roughly 1.2 × 10−2 sq in. Commercially available Hall generators which can be fitted into air gaps of approximately 0.011 in. have sampling areas in the order of 3.2 × 10−3 sq in. Hall generators with sampling areas in the order of 10−7 sq in. have been reported in the literature. Minimum thickness of this type device is presumably less than 0.01 in. The more recent work with the vibrating quartz crystal magnetometer has been used to measure flux density normal to the surface of permanent magnets. The sampling area of this type of equipment is 0.56 × 10−6 sq in. The minimum thickness of this equipment has not yet been reported in the literature.

The flux-measuring equipment being described in this paper has a sampling area of approximately 6.25 × 10−6 sq in. and a senstivity of approximately 0.01 × 10−3 v/gauss. The probe consists of a single turn inductor of length 116 in. which vibrates ±0.00005 in. The inductor is fastened to a probe of 0.01 in. thickness and the 0.0001 in. motion is perpendicular to this 0.01 in. probe thickness. The physical geometry and size of this probe permits measurements in a variety of positions relative to the magnetic circuit. This type of probe is applicable for measuring flux density in air gaps as small as 0.017 in.

The driving device for this equipment is a 60 Kcps magnetostrictive transducer. The complete probe consists of the transducer reactor, a coupling bar of nonmagnetic stainless steel and the thin strip of the nonmagnetic stainless to which the inductoris fastened. The geometry and size of this thin strip can be changed to accommodate variations in both inductor length and displacement.
Permanent Magnet Leakage Permeance Evaluation Based on Polar Radiation Analogy
Authors: Foy J. E. , Parker R. J.
Published: June 2005

This paper is based on the premise that the permanent magnetcan be considered as an equipotential body and hence electrostatic analogies can be used to advantage in evaluating permanent magnet leakage. The spherical pole formula, which is based on the substitution of a sphere having dimensions, which will make it the equivalent of the actual magnet limb in leakage effect, is described and its application to permanent magnet limb geometry is discussed. Evershed used this approach extensively with his work on the early steel permanent magnet. The authors review this work and explore the conditions affecting the use of this technique in modern permanent magnet materials.

Reversible permeability and limb magnet area to cross section area ratios are found to be influential in the location of the center of the effective polar regions. Today's high coercive force permanent magnet with shorter limb lengths is found to be particularly well-suited to this polar radiation analogy, since the departure from the spherical shape is less extreme than was the case with the earliest low coercive steel magnets. Calculation of demagnetization factors for rods, rings, “U” and “C” shaped magnets are convenient and accurate arrived at by this approach. A geometric criterion is developed which allows magnet configurations to be considered either (a) open circuit (permeance due to limb radiation),or (b) closed circuit magnets where the proximity of the polar regions is such as to increase the free polar radiation. In closed circuit magnet arrangements, the free polar radiation occurs for at least half the magnet limb area so that the spherical pole formula represents a very useful technique in the evaluation of any permanent magnet configuration.

To demonstrate the breadth of usage possible with the spherical pole formula a tubular-shaped magnet used as a magnetron field supply is analyzed to show the utility of this approach in estimating the shape of the axial field characteristic and its relationship to geometry and permanent magnet unit properties.
Experimental Flux Pattern Determination in Magnetic Cores
Authors: Ward Robert L.
Published: June 2005

The difficulties in determining the quiescent flux patterns in nonlinear magnetic structures is considered and two techniques are briefly described for measuring these patterns in magnetic cores etched from sub-mil thicknesses of 4–79 Molybdenum Permalloy. Both methods utilize a sensing loop formed by moveable surface probes and a part of the core itself, which conductively completes the sense circuit. A detailed description of the measuring apparatus and the testing technique is given, and the graphical procedure for plotting the flux configuration, of a two aperture multi-path core is outlined. Finally, additional applications are enumerated.
Interaction of Magnetic Crystals with Radiation in the Range 104–105 cm−1
Authors: Clogston A. M.
Published: June 2005

The optical absorption spectrum of magnetic crystals containing ferric iron in the range 104 to 105 cm−1consists of a series of sharp peaks superimposed on a strong absorption band. The absorption band is associated with a large Faraday rotation of the transmitted light. The sharp peaks are identified as transitions within the configuration (3d5). The broad band can arise either from an internal transition to (3d44p)or to a charge transfer process. Both mechanisms are able to account for the observed intensity and rotation within a factor of two. Because of the Faraday rotation, the charge transfer must be associated with d levels of symmetry Γ5. The rotation has the opposite sign for the two cases and could be used to distinguish between them.
Nuclear Resonance in Ferromagnetic Cobalt
Authors: Portis A. M. , Gossard A. C.
Published: June 2005

The observation of nuclear magnetic resonance in ferromagnetic cobalt is reported. The resonance frequency for finely divided face-centered-cubic material has been measured in the intermediate temperature range. The frequency extrapolated to 0°K is 217.2 Mc/sec, and the temperature dependence in this range is in general agreement with that of the magnetization. This frequency implies a hyperfine field of 217 500 oe, which is in good agreement with the field deduced from specific heat measurements on hexagonal cobalt. The agreement in the two structures indicates that there is no dipolar contribution to the hyperfinefield. The theoretical implications of this observation are discussed. The resonance line is inhomogeneously broadened with a half width of 400 kc/sec. A pattern of beats is observed at high passage rates which makes it possible to determine a spin-spin time of 25 μsec. By varying the modulation frequency under conditions of intermediate saturation the spin lattice relaxation time is measured to be 280 μsec. The resonance signal is remarkably intense, being 5×105 stronger than calculated for a dipole transition in the driving radio frequency field. It is shown from the saturation measurements that the rf field at the cobalt nucleus is 103 times stronger than the external driving field. These intensity and saturation measurements, as well as the observed line shape,establish that the resonance is driven by domain wall motion. Only those spins within the domain walls are affected. An external field reduces the intensity of the resonance but produces no shift in the resonance frequency. Both these effects are consistent with domain wall excitation. Spin-spin relaxation is interpreted as a spin wave coupling reduced in intensity by the broadening of the resonance spectrum. The spin-lattice relaxationis by spin diffusion away from the domain walls and ultimately to the lattice by coupling with the conduction electrons as suggested by the temperature dependence of the relaxation time.
Saturation Effects in Ferrimagnetic Resonance
Authors: Seiden P. E. , Shaw H. J.
Published: June 2005

Saturation curves of susceptibility as a function of rf magnetic field have been measured for a number of samples of polycrystalline yttrium iron garnet of varying linewidth. The curves exhibit a region of susceptibility linear in 1/hrf at high rf powers. The region of the initial decline in susceptibility is linear in hrf2,which is predicted both by a small signal relation derived from Callen's ferromagnetic dynamical equation and by a calculation of Schlömann which includes inhomogeneity interactions.

A new method of determining the critical field for spinwave build-up is discussed. This method takes account of the fact that the initial decline in susceptibility is not simply due to the Suhl mechanism for saturation in ferrites.
Effects of Hydrostatic Pressure on the Properties of Magnetic Materials
Authors: Alley R. E. , Legg V. E.
Published: June 2005

A review of the literature on hydrostatic pressure effects on magnetic materials showed a lack of information on technologically important properties such as initial permeability, and the hysteresis loop. Measurements of these properties up to 20000 psi showed that most solid materials are only slightly affected. These include tape cores of supermalloy, supermendur, 4–79 Mo-permalloy and grain-oriented Si-steel, as well as S-5 ferrite memory cores, and compressed powder cores of 2–81 Mo-permalloy or of carbonyl iron. Some types of NiZn and MnZn ferrite show increase of coercive force and decrease of permeability with pressure. Measurements were made of permeability vs frequency of MnZn ferrite to find the relaxation frequency. At atmospheric pressure, the permeability shows a sharp decline above 0.85 Mc. At 20000 psi the decline in permeability does not occur until 1.6 Mc.
Rigorous Solution of Eddy Current Losses in Rectangular Bar for Single Plane Domain Wall Model
Authors: Agarwal Paul D. , Rabins L.
Published: June 2005

Williams, Shockley, and Kittel, and other authors have presented a simple domain model in which magnetization takes place by the movement of a single plane domain wall. The net flux is zero when the domain wall is in the middle of the cross section and the material is magnetized fully when the wall moves to the surface.

Maxwell's equations for the case of a rectangular bar are rigorously solved for any position of the wall and expressions are derived for the current stream function in both regions I and II. The stream function was calculated using an IBM 705 computer and is shown for various positions of the wall and for several ratios of the sides of the rectangle. The power loss for sinusoidal applied induction is calculated. The results show that the loss in the material increases as the distance traversed by the wall, i.e., the dimension of the rectangle at right angles to the domain wall increases.

This solution with some modification also applies to thin laminations; where the domain model, proposed by several authors, consists of domains of equal width alternately magnetized in opposite directions to give the unmagnetized state. The domain walls are perpendicular to the plane of the sheet and magnetization in the sheet plane takes place by lateral movement of these domain walls. For any given thickness of the laminations, a domain wall spacing can be determined to correlate the power loss with experimental values.
GaFeO
3
: A Ferromagnetic-Piezoelectric Compound
Authors: Remeika J. P.
Published: June 2005

Piezoelectricity and ferromagnetism have been found to occur simultaneously in the compound Ga(2−x)FexO3. Single crystals of approximately equimolar gallium to iron ratio have been grown from a flux consisting of Bi2O3 and B2O3. X-ray diffraction data on ceramic compositions have shown that the galliumto iron ratio can be varied between x = 0.7 to x = 1.4. Magnetic data showing the shift in magnetic Curie point vs Fe concentration and magnetization vs Fe concentration will be given.
High-Temperature Susceptibility of Ferrimagnetic Spinels
Authors: Wojtowicz Peter J.
Published: June 2005

Power series expansions of the susceptibility and its inverse in ascending powers of the exchange divided by the temperature have been obtained for ferrimagnetic spinels by using the methods of Rushbrooke and Wood. The Heisenberg form of exchange is assumed, and in this paper, interactions between neighboring spins from different sublattices (A – B exchange) only are considered. The coefficients in the series are derived for arbitrary values of the spins on the two sublattices. The calculations have been carried out to terms including the fifth power of the exchange divided by the temperature; the molecular field theory by contrast is rigorously valid only to the first power term of its expansion. The explicit dependence of the Néel temperature on the spin values has also been deduced. The derived susceptibilities and Néel temperatures are compared to the results of earlier models. It is anticipated that these expansions will prove useful in the interpretation of accurate susceptibility data for the purpose of deriving meaningful values for the exchange interactions in the spinels.
Some Physical Properties of Thin Magnetic Films
Authors: Moore A. C. , Young A. S.
Published: June 2005

In films of nickel iron evaporated under suitable conditions, the magnetocrystalline anisotropy is averaged out by the random array of small crystallites. The stress in the films cannot be eliminated but its effect is made insignificant by using alloys whose mean magnetostriction is zero. In these particular films, no evidence is found of angle of incidence effect but it is shown that they may contain traces of oxide.

It is easier to obtain uniformity in magnetic properties of a number of elements in a plane if the magnetic film is made continuous and edge effects are excluded. No interaction takes place between adjacent areas when spaced 12 cm apart. This spacing can probably be reduced by a factor of at least two without interaction trouble.
Domain Wall Velocities in Thin Iron-Nickel Films
Authors: Ford N. C.
Published: June 2005

An apparatus based on the Kerr magneto-optical effect has been used to measure the velocity of domain walls in thin iron-nickel films. Polarized light, after being reflected by a film, is analyzed and detected by a photomultiplier tube. The slope of an oscilloscope trace resulting from the photomultiplier signal is directly proportional to the domain wall velocity, as the wall traverses a light spot of known size. Wall velocities are found to be well described by an equation of the form v = m(H−H0), where m is the wall mobility and H−H0 the excess applied field. Measurements have been made on films varying in thickness from 4000 A to 700 A with corresponding mobilities of 0.5×104 cm/sec-oe for the thicker film and 4.9×104 cm/sec-oefor the thinner film. The wall mobility is found to be inversely proportional to Bsσd where σ is the electrical conductivity and d the film thickness. This is the dependence that is predicted on the basis of a simple eddycurrent model indicating that, even in films as thin as 700 A, the dominant loss mechanism in wall motion is caused by eddy currents rather than intrinsic damping of the Landau-Lifshitz type.
Domain Walls in Thin Magnetic Ni-Fe Films
Authors: Methfessel S. , Middelhoek S. , Thomas H.
Published: June 2005

Néel proposed a transition from the normal type of domain wall (i.e., rotation of the magnetization vector in the plane of the domain wall) to the Néel type (i.e., rotation of the magnetization vector in the plane of the film) at a certain film thickness, which is due to the thickness dependence of the magnetostatic energy. It is suggested that the cross-tie walls observed in thin Ni-Fe films with uniaxial anisotropy correspond to such a transition, in which the cross ties serve to decrease the magnetostatic energy.

According to this explanation, such a structure should occur in a certain thickness range only. Experimental observations on Ni-Fe wedge-shaped films show the occurrence of the cross-tie structure in the thickness range 400–900 A, which is approximately that predicted by theory. The coercive force shows an anomaly in the same range.

The energy reducing function of cross ties is also shown by the Bitter patterns near scratches in the easy-direction in negative magnetostrictive material. In a region along the scratch, the magnetization in the plane of the film is perpendicular to the original easy direction due to the local stresses and again a cross-tie structure is observed.
Annular Uniaxially Magnetized Domains in Thin Ni-Fe Films
Authors: Muckenhirn O. William , LaBonte A. E. , Besser P. J.
Published: June 2005

Stable annular uniaxially magnetized domains have been observed in thin circular Ni-Fe films using both the Kerr and Faraday magneto-optic effects. The films exhibit unusual magnetic behavior in both the“easy” and “hard” directions. Generally the magnetization reversal begins at the circumference of the filmwith the appearance of a uniaxially magnetized annular domain whose inner radius then decreases with increasing applied field. In a number of films, the mechanism of magnetization reversal in an outer annular region appears to be distinctly different from that in the central region. In the annular region, the low-frequency magnetization reversal in the easy direction proceeds by wall motion with the Bloch walls approximately parallel to the direction of the applied field, but there is evidence that the reversal in the hard direction occurs by a rotational process. After the annular region is completely reversed, the center region is reversed by a radially inward motion of the circular boundary between the two concentric uniaxially magnetized domains. The magneto-optic observations are qualitatively correlated with 60 cps dφM/dt vsH and φM vs H loop data. Based on the assumptions of uniform magnetization per unit volume, M, and uniform film thickness, quantitative correlation of φM vs H as obtained from Kerr effect photographs and from normalized 60 cps hysteresis loop measurements have been made and are reported.
Hyperfine Interactions in Magnetic Materials by γ-γ Angular Correlation Measurements
Authors: Caspari M. E. , Frankel S. , Gilleo M. A.
Published: June 2005

A method for measuring hyperfine interactions in magnetic materials by γ-γ angular correlation techniques is discussed. The change in the anisotropy of the 1415-122 Kev γ-γ angular correlation following the K capture of Eu152 in neutron irradiated polycrystalline samples of Europium iron garnet enriched in Eu151 has been measured as a function of temperature without applied magnetic field, and the rotation of the angular correlation pattern has been observed when a magnetic field was applied perpendicular to the plane containing the γ counters. From these experiments, the effective magnetic field acting at the Europiumnuclei immediately after the radioactive decay can be obtained.
Magnetic Properties of Ferromagnetic Superconductors
Authors: Bozorth R. M. , Davis D. D.
Published: June 2005

Solid solutions of GdRu2 in CeRu2 are known to be superconducting and ferromagnetic. Magnetic measurements are reported for the 4 and 8% alloys; these show negative initial susceptibility (zero permeability)and hysteresis loops characteristic of superconductors. The 8% alloy shows typical ferromagnetic saturation and hysteresis at 5°K, and at 1.3° it appears to be both ferromagnetic and superconducting at the same time. Detection of ferromagnetism in the superconducting 4% alloy is difficult and could not be established.