bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Elektronenspinresonanz von strahlenerzeugten Radikalen in Einkristallen des 2,6‐Butylhydroxytoluols
Authors: Schoffa G. 
Published: July 2007

AbstractDie durch Röntgenstrahlen erzeugten stabilen Radikale in Einkristallen des 2,6‐Butylhydroxytoluols (BHT) geben bei Messungen der Elektronenspinresonanz eine aus vier Linien bestehende Hyperfeinstruktur mit dem Intensitätsverhältnis 1:3:3:1. Sie stammt von der Wechselwirkung des ungepaarten Elektrons des Semichinonradikals des BHT mit drei Protonen der Methylgruppe. Der fehlende anisotrope Anteil der Wechselwirkung spricht für die Rotation der Methylgruppe im Festkörper. Die Spindichten des BHT‐Radikals wurden nach dem MO‐SCF‐Verfahren nach McLachlan berechnet und mit den experimentell gewonnenen Spindichten verglichen.
Elektronenzustände in Halbleiterversetzungen
Authors: Güth W. , Haist W. 
Published: July 2007

AbstractMit Hilfe der Methode der effektiven Masse werden die Defektelektronenzustände einer Versetzungslinie berechnet. Es ergibt sich ein eindimensionales halbbesetztes Band in Richtung der Versetzungslinie, in dem die Defektelektronen quasifrei beweglich sind. In radialer Richtung zur Versetzungslinie sind die Defektelektronen stark gebunden, so daß die Versetzungslinie eng umgeben ist von einer Defektelektronenladungswolke, deren Halbmesser etwa gleich der Gitterkonstanten ist. Bei so eng begrenzten Elektroneneigenfunktionen liefert die Methode der effektiven Masse einen zu kleinen Wert der Bindungsenergie. Die unbekannten physikalischen Größen werden aus Messungen von Bliek und Schröter ermittelt, und die Rechnung wird diesen Werten angeglichen. Es gibt nur den radialsymmetrischen Defektelektronenzustand. Angeregte Zustände sind nicht stabil.
Effect of Pressure on the α‐Transition Point of Iron Monosulphide
Authors: Ozawa K. , Anzai S. 
Published: July 2007

AbstractThe temperature of the α‐transition point in FeS is investigated by electrical resistivity measurements with hydrostatic pressures up to 11 kbar. The transition point decreases linearly with increase of pressure at a rate of ‐(0.8 ± 0.1) deg/kbar.
The Importance of Vacancies and Interstitial Atoms in the Development of Induced Anisotropy
Authors: Lesnik A. G. , Levin G. I. , Nedostup V. M. 
Published: July 2007

AbstractExperimental data on the annealing of thin permalloy films in a magnetic field parallel to the axis of anisotropy are presented. The films are obtained by vacuum evaporation at the rate of 40 Å/s on glass substrates heated from room temperature to 200 °C. The shape of the isotherms of the anisotropy field (HK) depends upon the temperature of the substrate in various ways: 1) HK increases with annealing time up to saturation, 2) HK passes through a minimum, 3) HK decreases to a definite value. A quantitative description of the effects observed is given in terms of vacancy ordering and annihilation of vacancies and interstitials. The activation energies of these processes are calculated.
Effect of Tensile Stress on the Magnetic Properties of Permalloy Films
Authors: Lesnik A. G. , Sandler L. M. 
Published: July 2007

AbstractThe effect of tensile stress on the coercive force Hc, and anisotropy field HK, and on the angular and magnitude dispersions (bα and bK, respectively) of the anisotropy field is studied by the low frequency ferromagnetic resonance method. The stress is applied to the film so that the axes of anisotropy, induced by the effect of the stress and the field, coincide. It is shown that with increasing stress in the elastic range: 1) Hα increases, reaching saturation at a definite stress depending mainly on the film thickness and the magnetostriction constant, 2) HK increases linearly, 3) bα decreases, 4) bK is essentially unchanged. All these effects are reversible. The data obtained show that bα does not substantially affect the value of Hc Result 1) can be explained by a model in which Hc is determined by the roughness of the substrate surface, if the effect of stress on the width of the domain boundary is taken into account.
Anisotropy of the Conductivity of n‐Type Germanium at High Electric Fields
Authors: Dienys V. , Pozhela J. 
Published: July 2007

AbstractMeasurements of the hot electron conductivity anisotropy in germanium are made at lattice temperatures of 78 and 290 °K. The conductivity is measured both parallel and perpendicular to the direction of the high electric field. From the data the products n(i)〈τ〉(i) are obtained for each valley for fields in the 〈110〉 and 〈111〉 crystallographical directions. The electron “temperatures” and relative populations of the valleys are calculated. The results are not in agreement with the theory of Reik and Risken applied to n‐type germanium. The experimental results are compared with the theoretical ones obtained using the electron temperature approximation.
The Theory of the Cohesion of Noble Metals
Authors: Gubanov A. I. , Nikulin V. K. 
Published: July 2007

AbstractAn expression for the ground‐state energy of a metal is obtained, using many‐body theory and the pseudo‐potential method. Hence, using spectroscopic data, the cohesive energy, lattice constant and compressibility of Cu are calculated. The good agreement obtained between these results and experiment facilitates the complete explanation of cohesion in noble metals by the metallic bonding of the conduction electrons.
Low‐Temperature Heat Capacity and Thermodynamical Functions of Ferromagnetic Uranium Phosphide U3P4
Authors: Staliński B. , Bieganski Z. , Troć R. 
Published: July 2007

AbstractThe heat capacity of uranium phosphide, U3P4, is measured from 22.5 to 349.0 °K in an adiabatic calorimeter. A λ‐type anomaly is observed at 138.3 °K due to a ferromagnetic order‐disorder transition. Calculations are made of the thermodynamic functions, S0, (H0H), and ‐ (F0H)/T and the lattice and magnetic contributions to the heat capacity of this compound. The entropy change for the magnetic contributions to the heat capacity of this compound. The entropy change for the magnetic transition is estimated to be 3.09 cal mol−1deg−1.
Sur la structure de bandes des alliages HgTe‐CdTe I. Mesures électriques
Authors: Verié C. 
Published: July 2007

AbstractDes mesures électriques sont utilisées pour caractériser le régime intrinsèque des alliages CdxHg1−xTe pour 0 ≦ × < 0,30. On établit un traitement statistique simple de la distribution des porteurs, permettant de prédire l'évolution du régime intrinsèque en fonction de la température des semi‐métaux et semiconducteurs de bande interdite nulle ou faible, cristallisant dans la structure de la blende de zinc. Les conclusions du calcul, qui en particulier aboutissent à la définition d'un critère simple permettant de distinguer les semi‐métaux à faible recouvrement des semiconducteurs à très petite largeur de bande interdite, rendent compte des effets observés sur les trois séquences de compositions 0 ≦ × ≦ 0,10; 0,10 < × < 0,20; × ≧ 0,20 des alliages CdxHg1‐xTe.
Dependence of the geometry of the formation of X‐ray diffraction lines on the instrumental factors in X‐ray investigations of polycrystals
Authors: Davydov G. V. 
Published: July 2007

AbstractA stude is made of the dependence of the formation geometry of an X‐ray diffraction line on the instrumental factors for the case of recording the back‐reflection pattern from a polycrystalline flat‐layer specimen on a straight recording line lying in the focusing plane and parallel to the specimen plane. A general formula is derived for the position of the reflection of a ray that is emitted from any point of a three‐dimensional X‐ray source and reflected from the flat specimen at any point. A detailed study of the formation geometry of an X‐ray diffraction line is made for the two‐dimensional problem, the specimen and ray‐source having finite dimensions, and the focusing condition of the extreme rays holding. As for the three‐dimensional problem a solution is presented for the special case of the formation geometry of an X‐ray diffraction line for finite dimensions of the flat‐layer specimen and the point ray‐source under the focusing conditions of the extreme rays lying in the focusing plane. A number of examples has been selected for the calculations, the data are analysed and interpreted.
Zur Temperatur‐ und Feldabhängigkeit der galvanomagnetischen Eigenschaften von Aluminium und Indium
Authors: Lück R. 
Published: July 2007

AbstractEs werden Meßergebnisse des Hallkoeffizienten und der Widerstandsänderung im Magnetfeld von Aluminium und Indium in Abhängigkeit von der Temperatur (zwischen 4,2 und 273 °K) und von der Feldstärke mitgeteilt. Dabei hat sich eine Darstellung in einem Kohlerdiagramm als Funktion von ϱ/B als zweckmäßig erwiesen, da B/ϱ dem Produkt aus Zyklotronresonanzfrequenz ω und Relaxationszeit τ proportional ist. Beim Übergang vom einen Grenzfall ωτ ≪1 (Niedrigfeldfall) zum anderen ωτ≫ 1 (Hochfeldfall) ergibt sich aus dem Halleffekt für die Zahl der Elektronen pro Atom ein Übergang von 3 bis −1 in Übereinstimmung mit der bekannten Vorstellung von der Fermifläche. Die für Indium analog zu erwartenden Ergebnisse wurden nur zum Teil gefunden. Im Hochfeldfall folgt ebenfalls −1 für die Zahl der Elektronen pro Atom; jedoch wird im Niedrigfeldfall der entsprechende Wert nicht erreicht.
Die Temperatur‐ und Feldabhängigkeit der galvanomagnetischen Eigenschaften von Blei und der Einfluß der endlichen Probendicke hierauf
Authors: Lück R. 
Published: July 2007

AbstractDer Hallkoeffizient und die Widerstandsänderung in der Sondheimer‐ und in der MacDonald‐Sarginson‐Stellung (Magnetfeld senkrecht und parallel zur Probenoberfläche) von Blei werden in Abhängigkeit von der Feldstärke, dem Restwiderstand, der Probendicke und der Temperatur in einem Kohlerdiagramm angegeben. Es werden Korrekturen des Widerstandes und des Hallkoeffizienten für die endliche Probendicke ermittelt. Die Kohlerregel ist für die Widerstandsänderung und bei fester Temperatur auch für den Hallkoeffizienten nach erfolgter Korrektur für die endliche Probendicke erfüllt. Dagegen bringt der Temperatureinfluß Abweichungen von der Kohlerregel für den Hallkoeffizienten. Abweichungen von der Theorie der galvanomagnetischen Eigenschaften im Hochfeldfall bei gleicher Anzahl von Ladungsträgern verschiedenen Vorzeichens werden mit der Existenz einer offenen Fermifläche gedeutet.
Solvent diffusivity in a dilute B.C.C. binary alloy (weak perturbation case)
Authors: Gibbs G. B. 
Published: July 2007

AbstractThe effect of dilute alloying additions of a substitutional impurity on the diffusivity of a b.c.c. solvent is considered in terms of altered vacancy jump frequencies and vacancy‐solute binding energies, in the approximation that the impurity produces only a weak perturbation. An approximate expression for the impurity correlation factor is also derived.
Edge dislocation core structure and the peierls barrier in body‐centered cubic iron
Authors: Chang R. , Graham L. J. 
Published: July 2007

AbstractThe core structure and Peierls barrier for an edge dislocation lying in the {110} plane with Burgers vector along 〈111〉 in body‐centered cubic iron were investigated numerically with the aid of a high speed computer using an anharmonic potential. The core radius is about 5 Å and the corresponding core energy is 2.7 eV per identity distance along the dislocation line (six atom planes). The Peierls barrier is about 0.03 eV and the Peierls stress for dislocation motion at absolute zero is computed to be 5.36 × 109 dyn/cm2 or 0.0066 of the shear modulus.
Forward bias current‐voltage characteristics for a heterojunction in which tunnelling dominates
Authors: Tansley T. L. 
Published: July 2007

AbstractThe forward characteristics of a variety of heterojunction pairs have been observed to fit an empirical expression relating current, voltage, and temperature. This communication demonstrates that, given one basic assumption, the WKB approximation to tunnelling probability yields an analytic expression involving these three variables, which is found to be in qualitative agreement with experiment. Numerical results have been tested where possible and a resultant quantitative agreement is noted.
Temperature variation of the Grüneisen parameter of copper
Authors: Gupta R. P. , Sharma P. K. , Pal S. 
Published: July 2007

AbstractThe temperature variation of the Grüneisen parameter γ for copper is calculated from the observed pressure derivatives of the elastic constants using the electron gas model proposed by one of the present authors. Microscopic Grüneisen parameters, γq,i, are calculated as a function of the wave number q along the six directions [100], [110], [111], [210], [211], and [221] in reciprocal space and are averaged by a modification of Houston's spherical six‐term integration method. The calculated value of γ is found to be in good agreement with the experimental values of Rubin et al.
Localized 2S1/2‐state centres in ZnS
Authors: Räuber A. , Schneider J. 
Published: July 2007

AbstractElectron spin resonance is observed of photosensitive 2S1/2‐state divalent gallium, indium and thallium ions in ZnS. The ESR spectra show a large hyperfine interaction which may be greater than the energy of the microwave quantum. This suggests that the unpaired electron is highly localized at the impurity site. In contrast, the orbit of the unpaired electron of the shallow aluminium and halogen donors in ZnS exhibit considerable delocalisation.
On the determination of the nature of stacking faults in F.C.C. metals from the bright field image
Authors: van Landuyt J. , Gevers R. , Amelinckx S. 
Published: July 2007

AbstractA method is described whereby the nature of stacking faults in f.c.c. structures can be determined from the bright field image and the fine structure of the diffraction spots. The method is applied to stainless steel where the faults are found to be intrinsic. The procedure can easily be extended to similar problems where the slope of a planar interface has to be determined.
Temperatur‐ und Verformungsabhängigkeit der Koerzitivfeldstärke von Eisen‐Einkristallen (II)
Authors: Bilger H. 
Published: July 2007

AbstractDie Koerzitivfeldstärke von Eisen‐Einkristallen wird in Abhängigkeit von den Materialkonstanten und der Versetzungsdichte berechnet. Durch Vergleich der Theorie mit der gemessenen Verformungsabhängigkeit der Koerzitivfeldstärke läßt sich die Änderung der Versetzungsdichte während der plastischen Verformung bestimmen. Im Bereich I nimmt die Versetzungsdichte linear, im Bereich II quadratisch mit der Schubspannung zu. Ferner wird der Temperaturgang der Koerzitivfeldstärke unverformter und verformter Kristalle gemessen. Bei verformten Kristallen steigt die Koerzitivfeldstärke bis 600 °C stark an und fällt dann steil zum Curiepunkt ab. Die Magnetisierungsänderung bis etwa 600 °C erfolgt durch Blochwandbewegungen, oberhalb dieser Temperatur durch Drehprozesse. Die Koerzitivfeldstärke unverformter Kristalle bleibt bis etwa 250 °C konstant und nimmt nach höheren Temperaturen stetig ab. Dieser Temperaturgang wird entscheidend durch die Wechsel‐wirkung der Bereichsstruktur mit der Oberfläche (Schlauchziehpresse) bestimmt.
On the origin of the colour of labradorite
Authors: Bolton H. C. , Bursill L. A. , McLaren A. C. , Turner R. G. 
Published: July 2007

AbstractMeasurements have been made of the spectral distribution of the intensity of light reflected from a blue and a red labradorite for several angles of incidence over the wavelength range 3000 to 7000 Å. Transmission electron microscope observations of thin crystals of these labradorites show that the crystals consist of alternate light and dark lamellae of the order of 1000 Å thick. Although the pattern of the lamellae appears almost periodic, a statistical analysis indicates that the structure has no long‐range order. A theoretical discussion of the diffraction of light in such a structure is given and an expression for the spectral distribution of the reflected intensity derived. The spectral distributions to be expected from the blue and red labradorites have been computed using values of the mean thickness and variance of the alternate lamellae obtained from the electron micrographs. Satisfactory agreement between the observed and calculated spectral distributions is obtained. This supports an earlier suggestion that the colour of labradorite is due to optical interference in a lamellar structure.
The stress fields of dislocation tilt boundaries in anisotropic cubic and diamond‐type crystals
Authors: Duncan T. R. , Kuhlmann‐Wilsdorf D. 
Published: July 2007

AbstractThe shear stresses due to finite and infinite tilt boundaries consisting of {111},1/2〈110〉 dislocations, – naming slip plane and Burgers vector in order, – have been determined for the case of cubic anisotropy. These are the boundaries which in f.c.c. metals and diamond‐type crystals form due to polygonization. Their short‐range as well as long‐range stresses are discussed and compared to similar boundaries formed from {010} 〈100〉 edge dislocations and also from edge dislocations in the isotropic case. Quantitative curves are presented for a number of important f.c.c. metals and for germanium, silicon and diamond.
Elastic constants of some NaCl type alkali halides
Authors: Lincoln R. C. , Koliwad K. M. , Ghate P. B. 
Published: July 2007

AbstractSecond and third order elastic constants of NaCl, NaBr, KF, KCl, KBr, and RbBr have been calculated using the Born model of ionic solids. Short range repulsive interactions have been included up to second nearest neighbors using an expression of the form A exp (‐r/b) where b is the repulsive parameter. A distinction is made between the like and unlike ion interactions. Van der Waals terms are also included. When the room temperature lattice parameter is used, the elastic constants satisfy the Cauchy relations. Experimental data show that many of the alkali halides fail to satisfy the Cauchy relations. This aspect is examined by using the quasi‐harmonic approximation as developed by Leibfried and his associates. Linear temperature coefficients of the elastic constants are also calculated in the high temperature limit. In order to assess the contributions of the van der Waals terms, elastic constants are also calculated by dropping the van der Waals terms in the expressions for the elastic constants. Calculated values of the elastic constants are compared with the available experimental data.
Zur Anregungs–Rekombinationsstatistik in Halbleitern
Authors: Jungk G. 
Published: July 2007

AbstractFür einen Halbleiter mit einem Donator (Akzeptor) und einem Zentrum, welches mit beiden Bändern in Wechselwirkung steht, werden die kinetischen Gleichungen durch Vorgabe der Abweichung vom thermodynamischen Gleichgewicht vollständig gelöst. Für verschiedene Anregungsbedingungen (Grundgitteranregung, Störstellenanregung, gemischte Anregung) können beide Nichtgleichgewichtskonzentrationen für beliebige Abweichungen vom thermodynamischen Gleichgewicht berechnet werden. Als Anwendungsbeispiel sind Temperatur‐ und Intensitätsabhängigkeiten der Nichtgleichgewichtskonzentrationen in Silizium mit speziellen Störstellen dargestellt.
Approximate solution of Schön's balance equations for the thermoluminescence and the thermally stimulated conductivity of inorganic photoconducting crystals
Authors: Bräunlich P. , Scharmann A. 
Published: July 2007

AbstractThe present paper discusses approximate solutions of the well‐known balance equations for the kinetic electron processes occurring in thermoluminescence and thermally stimulated conductivity. Four cases are considered: in the first two cases the electron and hole retrapping rates are either both large or both small; the third and fourth cases involve one of these rates being large and the other small. The well known formulae for thermoluminescence due to Randall and Wilkins, and Garlick and Gibson are derived as special cases using certain simplifications.
On a simple derivation of the amplitudes of the electron beams transmitted and scattered by a crystal containing planar interfaces — images of subgrain boundaries
Authors: Gevers R. , van Landuyt J. , Amelinckx S. 
Published: July 2007

AbstractA calculation is made of the amplitudes of the waves transmitted and scattered by a plate‐shaped foil formed by the superposition of two parallel plate‐shaped crystals. The diffraction vectors, the excitation errors, the extinction distances, the absorption lengths, and the phase‐angles of the Fourier coefficients of the internal potential are assumed to be different in the two crystals. The amplitudes can be readily derived from the corresponding expressions for a perfect plate‐shaped foil. These expressions are found by considering the transmitted and scattered beams to arise from the interference of two plane waves with slightly different wave vectors. The method can be generalized to a plate‐shaped foil formed by the superposition of more than two parallel crystals. Assuming the column approximation to be valid a brief discussion is given of the different types of images resulting from planar interfaces. The images due to low angle subgrain‐boundaries are discussed in some detail and observations are presented. These images are often complicated by the superpositions of “wedge crystal” pseudo‐periodic fringe patterns and the “moiré” type of fringe patterns which are strictly periodic.
Infrared absorption by excitons due to photoionization and intraband lattice scattering
Authors: Moskalenko S. A. , Khadshi P. I. 
Published: July 2007

AbstractA quantum mechanical theory is developed for infrared absorption by excitons due to photoionization and intraband lattice scattering. The theory involves the interaction of the excitons with the acoustic and optical phonons. The Maxwellian and Bose‐Einstein distribution functions and the possible locations of the simple exciton band extremum are taken into account. The effect of the exciton photoionization is observable at the threshold frequency at comparatively low exciton concentrations.
Nuclear magnetic resonance of 63Cu and 65Cu in copper
Authors: Tompa K. 
Published: July 2007

AbstractThe anisotropy of the NMR spectrum of 65Cu is measured using copper foils with {100} 〈001〉 cubic texture. X‐ray diffraction measurements and NMR second moment calculations on the texture show that the “quasi‐single crystal” assumption can be used to interpret the second moment measurements. Investigations are made on the NMR of both copper isotopes in powder samples of various origins to elucidate the origin of the excess moment. The Ruderman‐Kittel interaction constant, Aij′/h computed for the first neighbours from the difference ΔM − ΔM between the excess moments is found to be (200 ± 50) Hz. The first order quadrupole effect due to impurities also contributes to the excess moment.
Untersuchung der Schwingungseigenschaften des Oszillistors
Authors: Elietner H. , Kempe N. 
Published: July 2007

AbstractDie Schwingungseigenschaften des Oszillistors werden in Abhängigkeit von der Größe des elektrischen und magnetischen Feldes und vom Winkel zwischen elektrischem und magnetischem Feld untersucht. Neben einer Grundmode, die in der Nähe der Schwellen‐werte des Schwingungseinsatzes rein auftritt, tritt unter bestimmten Bedingungen auch eine höhere Frequenz rein auf. Schwingungsbereich, Amplitude und Frequenz zeigen bezogen auf die Magnetfeldrichtung charakteristische Unsymmetrien, die sich besonders deutlich durch Änderung der Schwingungseigenschaften bei Umpolung des Magnetfeldes bemerkbar machen.