bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wechselwirkung zwischen Versetzungen und ebenen Blochwänden mit starrem Magnetisierungsverlauf
Authors: Pfeffer K. ‐H. 
Published: July 2007

AbstractMit Hilfe der Peach‐Koehlerschen Formel werden die Wechselwirkungskräfte zwischen 180°‐Blochwänden, deren Magnetisierungsverlauf als starr angenommen wird, und verschiedenen Versetzungskonfigurationen berechnet. Numerische Ergebnisse werden für die (110)‐ und (112)‐180°‐Blochwände in Nickel und für die (001)‐ und (110)‐180°‐Blochwände in Eisen angegeben. Die Temperaturabhängigkeit der für die verschiedenen Versetzungskonfigurationen charakteristischen effektiven Wechselwirkungslängen und die in der statistischen Analyse der Blochwandbewegung zu beachtenden geometrisch‐statistischen Parameter werden diskutiert.
Preferred Orientation and Domain Structure of Iron Films Deposited on (100) Copper Substrates
Authors: Jones G. A. 
Published: July 2007

AbstractThin films of iron are deposited both by electroplating and by evaporation, on (100) foils of copper. They display a well‐defined preferred texture with (110) planes parallel to the substrate. The shape, orientation, and size of the grains are discussed. Magnetic observations of the domain structure using electron microscopy show that the layers are effectively biaxial. Near thicknesses of 500 Å cross‐tie walls appear, which is in accordance with energy considerations. Finally, torque measurements lead to a value for K1.
A disorder model of melting and melts
Authors: Eckstein B. 
Published: July 2007

AbstractVarious thermal properties of molten metals are calculated assuming a strong correspondence between the crystal and the melt. Thus, the properties of melts are composed of a “lattice dependent” term, essentially equal to the value of the property for the crystal at its melting point, and a “defect dependent” term, calculable from the theory of crystal defects. The defect concentration in the melt is estimated from the volume increase due to melting. The calculated values agree fairly well with experimental data.
The effect of heat treatment on silicon nitride layers on silicon
Authors: Thomas D. J. D. 
Published: July 2007

AbstractOn heat treatment, structural changes may occur in silicon nitride layers deposited on silicon substratres by the glow discharge technique. The causes of the cracks and holes produced in the layer are shown to be thermal stresses and lack of adhesion between the layer and the substrate. Layers produced at above 600 °C, and particularly from silicon tetrachloride, remain perfect on heating up to 1200 °C. Dislocations are introduced into the silicon substrate at defects in the nitride layer. Deformation is produced by slip in the (111) planes parallel to the silicon surface. No defects are introduced into the silicon if the nitride layer remains perfect.
On the Operator of Exciton‐Phonon Interaction
Authors: Davydov A. S. 
Published: July 2007

AbstractA general expression for the operator for the interaction of molecular excitons with acoustic and optical phonons is obtained in a linear approximation. An explicit expression is found for the dependence of exciton‐phonon interactions on their wave‐vectors for a one dimensional crystal and for crystals of cubic, rhombic and tetragonal systems. The results obtained are compared with the operator for the interaction of free electrons and Wannier excitons with acoustic and optical vibrations in ionic crystals.
Refraktionsmodifizierte Braggsche Beugung bei asymmetrischer Rückstrahl‐Reflexion
Authors: Kunze G. 
Published: July 2007

AbstractDa das normale Braggsche Gesetz wegen Vernachlässigung der Refraktion vielen festkörperphysikalischen Präzisionserfordernissen nicht mehr gewachsen ist, wurde auf der Basis der kinematischen Theorie der Röntgeninterferenzen für den Allgemeinfall der asymmetrischen Rückstrahl‐Reflexion von ebenen Objekten ein allgemein gültiges Beugungsgesetz aufgestellt. Es gilt uneingeschränkt für Kristalle mit reellen Brechungsindizes und damit auch für lichtoptische Beugungserscheinungen an oder in nicht (oder höchstens schwach) absorbierenden Kristallen mit (quasi‐) superperiodischen Inhomogenitäten (Antiphasenordnungsdomänen, Entmischungszonen, Ausscheidungslamellen, etc.).
Thermally Stimulated Currents without Optical Excitation. Application to Copper Phtalocyanine
Authors: Devaux P. , Schott M. 
Published: July 2007

AbstractThermally stimulated current peaks can occur int he absence of previous optical excitation, if at least one of the electrodes on the sample is non‐ohmic. A variety of cases is considered. Most of these cases enable deep‐lying centres which give only very small current peaks to be studied. Their experimental characteristics are presented. They are particularly useful in the case of organic crystals, where optical filling of traps at low temperatures is inefficient and lengthy. This method, applied to copper phtalocyanine, enables centres lying at depths of 0.41 and 0.65 eV, which can not be observed using optical excitation, to be studied.
F‐Center Formation by Fundamental Absorption in KI
Authors: Goldstein F. T. 
Published: July 2007

AbstractIrradiation of KI in the fundamental edge results in a temperature dependent rate of F‐center growth predominantly proportional to the inverse of the number of F‐centers already produced. This is related to a new experimental result – the quenching of low temperature luminescence in irradiatively colored crystals. In addition, the production of F‐centers by absorption in perturbed exciton bands and the intrinsic production of α‐centers are discussed.
Mössbauer Effect in Iron‐Aluminium Alloys (II)
Authors: Cser L. , Otanevich J. , Pál L. 
Published: July 2007

AbstractThe concentration‐dependence of the isomer shift in iron‐aluminium alloys near the composition Fe3Al is investigated at various temperatures and found to be non‐monotonic. At the temperature of Fe3Al‐type ordering, the isomer shift exhibits a fairly pronounced discontinuity the value of which changes sign with increasing aluminium content. The width of the central line is found to be very broad in the temperature range 550 to 650 °C if the cooling rate is high. This phenomenon can be explained by assuming a transient disordering in the A‐type sublattice which introduces ordering of the D‐type sublattice.
Non‐Ideal Diffusion of Argon in Potassium Chloride
Authors: Schmeling P. 
Published: July 2007

AbstractThe diffusion of Ar39 and Ar41 in single crystals of potassium chloride is studied for the temperature range in which non‐ideal diffusion is predominant. The results are compared with the analysis of obstructed rare‐gas movement by Gaus, and it is shown that all or most of the argon atoms are trapped in crystal defects after irradiation with neutrons. The mechanism for the release of the atoms is sensitive to variations in the irradiation dose and can be related to an activation energy of 2.4 eV only for the lowest doses.
Te and Se Centres in AgBr. I. The g‐, Superhyperfine, and Hyperfine Tensors
Authors: Höhne M. , Stasiw M. 
Published: July 2007

AbstractIrradiation of AgBr:Te or AgBr:Se with green light at about 180°K produces a paramagnetic centre. It will be shown by investigation of the angular dependence of g‐values, superhyperfine structure, and hyperfine structure that the centre has orthorhombic symmetry, consists of two equivalent impurity anions and strongly interacts with two bromine ions.
Evaluation of the Debye Temperature of Thorium Dioxide
Authors: Ali M. , Nagels P. 
Published: July 2007

AbstractThe Debye temperature of ThO2 is calculated using existing data for heat capacity, neutron diffraction and elastic constants. The resulting values are 259, 268, and 290 °K, respectively. Attention is drawn to the existing confusion in the definition of the Debye temperature which involves the inclusion or exclusion of a factor \documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt[3]{3} $\end{document} depending on how the vibrational units are defined.
Unified Theory of Thermionic and Field Emission from Semiconductors
Authors: Christov S. G. 
Published: July 2007

AbstractThe recently developed general theory of electron emission from metals is extended to semiconductors assuming an arbitrary position of the Fermi level at the surface, and a parabolic energy‐momentum relation with an electron effective mass differing from the free electron mass. The expressions obtained for the emission current density from the conduction band are valid for all emission condition between the limits of thermionic and field emission. The formulae for the current originating from the valence band apply to wider emission conditions than those proposed in earlier work.
Higher Order Elastic Constants and the Equation of State of F.C.C. Metals
Authors: Rose M. F. 
Published: July 2007

AbstractA central potential function is used to calculate the elastic constants through fourth order. It is assumed that the vibrational contribution to the free energy of a solid is given by \documentclass{article}\pagestyle{empty}\begin{document}$ F_{vib} = kT\sum\limits_{i = 1}^{3SN} {\ln 2\sinh \left\{ {\frac{{h\omega _\iota }}{{2\kappa {\rm T}}}} \right\}} $\end{document} and from this, the temperature dependence of the third order elastic constants are calculated. These data are then used to calculate the equation of state of copper, silver, aluminum, and nickel. Agreement between experimental and theoretical equations of state is quite good for pressures as high as 400 kbar.
Stacked Screw Dislocation Arrays in an Anisotropic Two‐Phase Medium
Authors: Chou V. T. , Barnett D. M. 
Published: July 2007

AbstractThe distribution of screw dislocations under an applied stress in uniformly stacked pileups against a second phase is determined. The number of dislocations, n, in each pileup decreases as the separation h between pileups decreases and as the ratio of the shear moduli of the second and the matrix phases (G″/G′ in the isotropic case) increases. The stress field produced in the second phase is quantitatively described. For L/η′ ≫ x/η″, the intensity of the stress field at a distance x from the tip of each pileup varies as \documentclass{article}\pagestyle{empty}\begin{document}$ \left({\tanh \frac{{\pi L}}{{\eta \prime h}}/\tanh \frac{{\pi x}}{{\eta \prime \prime h}}}\right)^\lambda $\end{document} where L is the length of the pileup, η′ and η″ are respectively functions of the elastic constants of the matrix and the second phases, and λ is a monotone decreasing function of the ratio of the shear moduli, varying in the range 1 > λ > 0 as the ratio varies between 0 and ∞. The stress concentration near the tip thus decreases as h decreases and as the modulus ratio increases. A number of special cases derived from the general solution are discussed.
Die Richtungsverteilung der Frequenzen von Gitterschwingungen einer festen Wellenzahl
Authors: Mika K. 
Published: July 2007

AbstractZur Berechnung der Richtungsverteilung gq(ω) von akustischen Schwingungsfrequenzen vorgegebener Wellenzahl q werden die „kritischen Punkte”︁ von Dispersionsflächen ωs(θ φ)gesucht. Am Beispiel der kubisch primitiven Gitter werden diese Flächen in der Umgebung der Symmetrierichtungen diskutiert, im linearen Dispersionsbereich werden hierdurch gleichzeitig sämtliche kritischen Punkte festgelegt. Das sich hieraus ergebende Spektrum gq(ω) zeigt Merkmale wie das von van Hove untersuchte Gesamtspektrum eines zwei‐dimensionalen Kristalls.
On the Magnetocrystalline Anisotropy of NiCo Ferrites
Authors: Elbinger G. 
Published: July 2007

AbstractThe magnetocrystalline anisotropy of CoxNi1−xFe2O4 ± γ is measured at room temperature by torque measurements. It is found that an additional couple caused by the anisodropy of the magnetization must be taken into account in the determination of the magnetocrystalline constants. For the (100)‐plane is found that the magnetocrystalline anisotropy increases nearly linearly with the Co‐content. The constants k1 of the anisotropy of the magnetization also increase linearly at low Co‐additions, but at higher Co‐concentrations the increase is less than linear. Measurements in the (111)‐plane show a marked dependence of Lmax on the magnetic field strength. Attempts to find the values of the constants by extrapolation prove unsuccesful.
A Source of Dislocations in Copper Crystals
Authors: Clarebrough L. M. , Michell D. , Smith A. P. 
Published: July 2007

AbstractIn single crystals of copper annealed in hydrogen, dislocations are generated by prismatic punching during cooling at 3 °C/s. The centres of punching are voids formed by vacancy clustering and the stress necessary to generate dislocations arises from an internal pressure of hydrogen in the voids.
Thermally Stimulated Currents under the Condition of Persistent Internal Polarization
Authors: Zolotaryov V. F. , Semak D. G. , Chepur D. V. 
Published: July 2007

AbstractA new method is proposed for direct determination of the trapping levels which are responsible for internal polarization in semiconductors. The method is based on the fact that internal polarization, i. e. the internal field, becomes important at low temperatures. In the presence of the internal field, the trapping levels are then investigated by the thermally‐stimulated‐current method. The internal field affects the temperature dependence of the thermally stimulated current. The thermally stimulated current shows a quadratic dependence on carrier concentration in the conduction band. This is the reason for the contraction of the thermally stimulated current maxima and the improvement in their separation.
Electrical Resistivity in Antiferromagnetic Alloys
Authors: Masharov S. I. 
Published: July 2007

AbstractA generalization of the s‐d–exchange model developed for domains in binary antiferromagnetic alloys is presented. It is shown that departures from the the ideal periodicity in the distribution of atoms among the lattice sites leads to a number of interaction processes between elementary excitations in the electron and spin sub‐systems which do not occur in ideal antiferromagnetics. In particular, electron‐magnon collisions arise which do not conserve quasi‐momentum. In the low temperature range these effects are dominant in the scattering of conduction electrons, giving rise, to a term proportional to T2 in the electrical resistivity.
Theory of Resonant Secondary Radiation due to Impurity Centres in Crystals
Authors: Hizhyakov V. , Tehver I. 
Published: July 2007

AbstractThe resonant secondary radiation spectrum of impurity centres in crystals is studied on the basis of a second‐order approximation for the interaction between the electromagnetic field and the material. It is shown that for the case of excitation in the phonon wing of the absorption band, the main part of the secondary radiation represents the ordinary luminescence. The spectrum also contains Rayleigh and Raman scattering which is considerably weaker (by about four orders of magnitude). Formulas are obtained for the intensities of Rayleigh‐ and Raman scattering; particular consideration is made for the case of large Stokes' losses. It is also shown that excitation in the region of the pure‐electronic line yields a spectrum consisting of the Rayleigh and the pure‐electronic line, and the phonon wing of the luminescence.
Generation–Recombination and Diffusion Noise in Cadmium Sulphide Photoconductors
Authors: Damodar‐Pai M. , van Vliet K. M. 
Published: July 2007

AbstractNoise in CdS stemming from generation–recombination, trapping, diffusion, and drift is investigated. In the treatment, the transport equations corresponding to a four‐level model are considered. Closed form expressions for the various parts of the spectrum and for the pertinent relaxation times are given. Experimental results demonstrated many features of the computed spectra, particularly for absorption in the long‐wavelength tail. Some quantitative values for the rate constants and effective diffusion constants are derived. The relative variance of the spectra, <ΔN2>/N0 is found to be close to unity.
Zur Auswertung isochroner Ausheilkurven
Authors: Balarin M. , Rattke R. , Zetzsche A. 
Published: July 2007

AbstractEs wird gezeigt, welche Unterschiede zu beachten sind, wenn die für zeitlineare Erholungskurven bekannten Auswertungsmethoden zur quantitativen Bestimmung der Aktivierungsenergie auf isochrone Erholungskurven übertragen werden sollen. Es werden behandelt: die Auswertung des Verlaufs einer einzelnen Erholungskurve und die Auswertung der Temperaturverschiebung infolge unterschiedlicher Aufheizgeschwindigkeiten.
The Use of the Magneto‐Optical Kerr Effect for the Determination of Magnetization Curves
Authors: Stoll M.‐P. 
Published: July 2007

AbstractMagnetization curves obtained by means of magnetooptical Kerr rotation show important differences from the usual curves. This phenomenon is assumed to be related to the spatial distribution of the local directions of magnetization. In the case of polycrystalline samples, the rotation may be calculated for weak applied fields, and this is in good agreement with the experimental curves. The results indicate that a surface pinning effect is likely to occur. For single‐crystal mirrors, the magneto‐optical curves are, in special cases, similar to the usual magnetization curves in the high field region.
An Analysis of the Cottrell‐Stokes Law
Authors: Evans K. R. , Flanagan W. F. 
Published: July 2007

AbstractThe retarding force profiles available for copper and its solid‐solutions are shown to explain reported deviations from the Cottrell‐Stokes law. It is shown that the Cottrell‐Stokes law is not valid and only approximated when a large athermal force must be overcome by an applied stress attempting to translate a dislocation segment past a rate‐controlling obstacle to dislocation motion.
On the Theory of Electrical Domains in Hot Electron Semiconductors
Authors: Bonch‐Bruevich V. L. 
Published: July 2007

AbstractAn analysis is given of the conditions under which exist stationary moving domains in hot electron semiconductors. The criteria for soft and hard regimes of domain excitation are obtained. It is shown that several domain modes may exist which propagate with different velocities. The problem of the current oscillations in the external circuit is considered briefly and the conditions under which such oscillations appeare are stated.
The Second Ferroelectric Phase Transition in NaH3(SeO3)2 Crystals and their Physical Properties
Authors: Shuvalov L. A. , Ivanov N. R. 
Published: July 2007

AbstractAn investigation is made of the spontaneous polarisation, the coercive field, the dielectric constant, the electro‐optical behaviour, and the domain structure of ferroelectric NaH3(SeO3)2 single crystals in the temperature range −195 to 0 °C. The existence of two phase transitions and two ferroelectric phases is confirmed; the presence of two domain systems and a contribution of this domains to the dielectric constant in the triclinic ferroelectric phase is observed. The multiaxial electrical behaviour of the crystals in this phase, the enantiomorphism of the domains, and other peculiarities of electrical twinning are discussed. A large difference is noted in the behaviour of the mutually orthogonal components of the spontaneous polarization.
Contribution of Thermal Vibrations to the Anomalous Transmission of X‐Rays
Authors: Efimov O. N. 
Published: July 2007

AbstractThe contribution of the thermal vibrations to the real and imaginary parts of the structure factor is discussed on the basis of experimental temperature dependences of integral characteristics for the anomalous transmission of X‐rays in germanium between 85 and 650 °K. The deviation of the temperature dependence of the imaginary part of the structure factor from the form Fihe−M (M Debye‐Waller factor) is in good agreement with a theoretical analysis. This analysis takes into account the contributions from phonon scattering on phonons by considering a dynamic solution of the problem.
On the Theory of Spontaneous Hall Effect at Low Temperatures
Authors: Irkhin Yu. P. , Voloshinskii A. N. , Abelskii Sh. Sh. 
Published: July 2007

AbstractA study is made of the spontaneous Hall effect in ferromagnetic metals caused by the anisotropy of the scattering of conduction electrons by spin waves. The temperature dependence of the spontaneous Hall coefficient is given by Rs = α T3 + β T4, where the first term is due to the interaction of the conduction electron orbits with the spins of the magnetic electrons and the second term is due to the spin‐orbit interaction between the magnetic electrons themselves.
Phase Diagram of the Alloy System HgTeCdTe
Authors: Ray B. , Spencer P. M. 
Published: July 2007

AbstractThe solidus and liquidus for the pseudo‐binary alloy system HgTeCdTe has been determined with differential thermal analysis and X‐ray techniques. Solid solution exists throughout the system. The liquidus deviates slightly from the linear but the solidus rises very slowly with increasing CdTe concentration to approximately 40 mol%. At higher concentrations the increase is more rapid.
The Effect of the Type of Splitting of Screw Dislocations on the Slip Geometry in B.C.C. Metals
Authors: Vítek V. 
Published: July 2007

AbstractA theory of slip geometry in b.c.c. metals is given which is based on the assumption that the sessile‐glissile transformations of the splitting of screw dislocations are continually repeated during their motion. The sessile splitting is assumed to occur via the reaction 1/2 [111] = 1/6 [111] + 1/6 [111] + 1/6 [111] on a {110} and a {112} plane simultaneously as proposed by Foxall, Duesbery, and Hirsch [14]. The theory is developed analogically as in [8] where a different type of splitting was used. The previous results are compared with the present results for Fe‐3% Si and niobium.
The Influence of Carbon on Precipitation of Copper in Silicon Single Crystals
Authors: Fiermans L. , Vennik J. 
Published: July 2007

AbstractThe effect of carbon on the copper precipitation behaviour of dislocation‐free silicon crystals with low oxygen concentration, is studied by infra‐red microscopy, high‐resolution X‐ray topography and infra‐red spectrophotometry. A growth mechanism is proposed for the copper precipitates which is based on indentation at silicon carbide or silica precipitates, followed by climb of dislocation loops. The main type of dislocation likely to produce the observed pattern, is thought to be the 〈100〉 edge dislocations.
Dielectric and Optical Absorption Measurements on CaF2 and CaF2:Y
Authors: Caffyn J. E. , Goodfellow T. L. , Olymbios E. M. , Perrin D. J. 
Published: July 2007

AbstractCrystals of oxygen free and oxygen contaminated CaF2 were doped with yttrium. The dielectric loss of the unirradiated crystals was measured at 150 °C at different frequencies and a shift of the peak in the curves was found with varying concentration of yttrium. In oxygen free crystals the peak was displaced to higher frequencies whilst with oxygen contaminated crystals the shift was to lower frequencies. The optical absorption spectra were taken at room temperature before and after room temperature X‐irradiation. The uv optical absorption that exists in oxygen contaminated crystals even before X‐irradiation was found to decrease in yttrium doped crystals grown from oxygen contaminated material. It is proposed that the observed results could be explained on the assumption that one or more of the following associated defects are present in the crystals, namely: 1. an oxygen ion and fluorine ion vacancy, 2. an yttrium ion and an interstitial fluorine ion, 3. an yttrium ion and a substitutional oxygen ion. The shift of the dielectric loss peak to lower frequencies for yttrium doped oxygen contaminated crystals is correlated with the reduction of the uv optical absorption. It is suggested that possible explanation for this reduction is due to the formation of yttrium—oxygen dipoles. Thermal annealing of these crystals provides further confirmation of this suggestion.