bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of the Non‐Equilibrium Depletion in Germanium at the Electrolyte Interface
Authors: Konorov P. P. , Shvetsov V. N. , Shegolikhina S. V. 
Published: July 2007

AbstractNon‐equilibrium depletion effects in thin high resistivity n‐type germanium specimens during anodic polarization in an electrolyte are investigated by conductivity and Hall effect measurements. It is shown that first diffusion depletion by minority carriers takes place which spreads practically over the whole specimen when the thickness of the specimen is much less the diffusion length of minority carriers. A further increase of the polarization leads probably to a breaking of the inversion layer formed on the n‐type germanium surface during anodic polarization. In this case the field penetrates deep into the specimen and causes the appearance of a region near the germanium–electrolyte interface depleted by both electrons and holes. An estimate shows that the thickness of this region is not less than 40 μm. In the state of non‐equilibrium depletion, the sample sensitivity for generating minority carriers increases considerably; this is especially important for the Hall effect.
Paramagnetic Resonance of Silver Atoms Stabilized in Alkali Halide Crystals
Authors: Baranov P. G. , Zhitnikov R. A. , Melnikov N. I. 
Published: July 2007

AbstractStabilized silver atoms are obtained at 77 °K by irradiating alkali halide crystals (LiCl, NaCl, and KCl) containing silver ions with X‐ray. The properties of these stabilized atoms are studied by PR (paramagnetic resonance). It is found that the silver atoms occupy the cationic sites of the crystals studied. The dependences of the hyperfine and superhyperfine interaction constants on the lattice constant, i.e. on the distance from the surrounding chlorine ions, are studied. The temperature dependences of the hyperfine and superhyperfine structure constants of silver atoms in the case of LiCl: Ag are also studied.
Theoretical Study of Properties of Copper and Silver Atoms Stabilized in Alkali Halide Crystals
Authors: Baranov P. G. , Zhitnikov R. A. , Melnikov N. I. 
Published: July 2007

AbstractA theoretical analysis of the hyperfine and superhyperfine interaction of copper and silver atoms stabilized in alkali‐halide crystals [1 to 4] is carried out. The hyperfine interaction is investigated on the basis of Adrian's theory [5] whose application to atoms stabilized in ionic crystals requires its further development. Particularly, the influence of the crystal field is taken into account. The results of theoretical calculations of hyperfine and superhyperfine interaction constants of copper and silver atoms in the lattices of alkali halide crystals are given. The overlap integrals for the wave functions of the unpaired electrons of copper and silver atoms and the wave functions of the nearest chlorine ions are calculated. The results of these theoretical calculations show a reasonable good agreement with the experimental data previously obtained [1 to 4].
Ferromagnetic Resonance in Ga0.85Fe1.15O3
Authors: Petrov M. P. , Kizhaev S. A. , Smolenskii G. A. 
Published: July 2007

AbstractThe angular dependences of the position and width of the ferromagnetic resonance line in Ga0.85Fe1.15O3 are investigated. An anomalous angular dependence of the line width is found. The anisotropy fields for intermediate and easy magnetic directions are calculated. The effect of an electric field on the position of the ferromagnetic resonance line is discussed.
Influence of the Electron Scattering Anisotropy upon the Phonon Drag Effect in n‐Ge and n‐Si
Authors: Iskra V. D. , Gostyuk G. T. 
Published: July 2007

AbstractThe Boltzmann equation is used to study the influence of the scattering anisotropy upon the phonon drag effect in n‐Ge and n‐Si. Assuming the electrons to be scattered mainly by acoustical phonons and the only mechanism of the phonon relaxation to be phonon‐phonon scattering, explicit formulae are obtained for the components of the thermoelectric force tensor due to a single valley as well as for the total thermoelectric force. Composition with the experimental data allows to evaluate both contribution of the transverse phonons to the drag effect and the interaction parameters for the longitudinal and transverse phonons.
Dielectric Function of Semiconductors
Authors: Kübler J. K. 
Published: July 2007

AbstractThe real part of the dielectric function ϵ(q, ω) is obtained in the random phase approximation for semiconductors. If the first interband transition is forbidden, the following limits are obtained from the general formula for ϵ(q, ω) involving a finite energy gap EG: EG → 0, ω = 0, then ϵ(q, 0) ∝ q−1; EG → 0, q = 0, then ϵ(0, ω) ∝ ω−1/2; EG small, q = ω = 0, then ϵ(0, 0) α EG−1/2.
Atomistische Behandlung von Kinke und Sprung einer Stufenversetzung in NaCl. I. Die Kinke
Authors: Eisenblätter J. 
Published: July 2007

AbstractEs wurde zunächst die Energie der abrupten Kinke im Bornschen Modell des Ionenkristalls berechnet. Da diese näherungsweise quadratisch von der Kinkhöhe abhängt, war es möglich, die Betrachtung des allmählichen Übergangs bei der Kinke auf ein etwas abgewandeltes Frenkel‐Kontorova‐Modell zurückzuführen. Die Ergebnisse sind in guter Übereinstimmung mit denen von Seeger u.a.
Theory of Ultrasonic Attenuation by Magnetic Surface States in Metals
Authors: Fischbeck H. J. , Mertsching J. 
Published: July 2007

AbstractA theoretical expression for the resonant absorption of longitudinal ultrasound by magnetic surface states is given, and the basic physical ideas are explained. The interaction matrix element showing quasi‐geometric oscillations is calculated and discussed, and the order of magnitude of the absorption is estimated. The experimental realization of the effect appears to be very difficult. From the theoretical point of view it is pointed out that on favourable conditions such ultrasonic investigations should be more convenient for determining the relevant physical parameters than microwave experiments.
Leerstellenausheilung in Platin nach Abschrecken unter Argonatmosphäre und in Wasser
Authors: Rattke R. , Hauser O. , Wieting J. 
Published: July 2007

AbstractEs wird über Untersuchungen zum Ausheilverhalten abgeschreckter Platinproben in Abhängigkeit von der Abschrecktemperatur, der Abschreckgeschwindigkeit und vom physikalischen Zustand der Proben berichtet. Dabei zeigt es sich, daß niedrige Wanderungsenergien für Leerstellen von 1,0 bis 1,1 eV unabhängig von der eingefrorenen Leerstellenkonzentration immer dann erhalten werden, wenn bereits vor dem Abschrecken eine hohe Versetzungsdichte vorliegt oder wenn bei hohen Abschreckgeschwindigkeiten durch Verformungen während des Abschreckens die Senkendichte verändert wird. Höhere Wanderungsenergien von 1,3 bis 1,4 eV treten bei gut vorgeglühtem Material und hinreichend langsamen Abschreckgeschwindigkeiten ebenfalls unabhängig von der Leerstellenkonzentration auf. Sie sollten der freien Wanderung von Einzelleerstellen zugeschrieben werden, während die kleineren Energien zusätzliche Wechelwirkungen mit den Senken enthalten. Unter diesen Umständen stellt die chemische Reaktionsgleichung keine gute Näherung für die Beschreibung des Ausheilvorganges dar. Ein Einfluß von Doppelleerstellen auf die Ausheilung kann erst erfaßt werden, wenn bei hinreichend senkenarmem Material eine Verformung während des Abschreckens ausgeschlossen werden kann.
Trägerbeweglichkeit in verformtem Germanium
Authors: Schröter W. 
Published: July 2007

AbstractDie Hallbeweglichkeit schwach dotierter Germaniumeinkristalle wurde vor und nach plastischer Verformung zwischen 50 und 250 °K gemessen. Die streuenden Verformungszentren wurden als Versetzungen identifiziert, die durch ihre Ladung und ihr Verschiebungsfeld die Beweglichkeit freier Löcher beeinflussen. Zur Bestimmung der Ladung der Versetzung wurde das Modell des Versetzungsbandes herangezogen. Die Ergebnisse der Beweglichkeitsmessung wurden unter der Annahme analysiert, daß freie Löcher bzw. ionisierte Fremdatome die Versetzungsladung abschirmen.
Measurements of the Zener Effect and Kinetics of Short‐Range Order in Two AuCu Alloys (Containing 14 and 25 at% Cu)
Authors: Radelaar S. , Ritzen J. M. J. 
Published: July 2007

AbstractMeasurements of the Zener relaxation effect and resistivity measurements of the establishment of short‐range order in two AuCu alloys (containing 14 and 25 at% Cu, respectively) are described. The relaxation times of both effects agree quite closely for the 14 at% Cu alloy. However, for the 25 at% Cu alloy the relaxation time determined from the resistivity measurements shows an anomalous increase as the critical temperature for long‐range order is approached from the high temperature side. This effect is discussed in terms of a current model for short‐range order above the critical temperature. The activation energies obtained from the Zener effect data are compared with the results of quenching experiments in these alloys.
Quenched‐in Electrical Resistivity of Dilute Binary Alloys
Authors: Liu G. C. T. , Girifalco L. A. , Maddin R. 
Published: July 2007

AbstractThe quenched‐in electrical resistivity of dilute binary alloys has been calculated, assuming that the alloy system contains single vacancies, di‐vacancies, single solutes (impurities), di‐solutes, and solute—vacancy pairs in an otherwise perfect matrix. Some numerical computations have been made for dilute binary alloys of Au. By assuming that the electrical resistance of a point defect in the paired or associated state is less than that of the unpaired or single state, it is shown that the solutes do have a significant effect on the quenched‐in electrical resistivity if the perturbation introduced into the alloy by the solutes is large. For instance, the change of the binding energy or the concentration of solute‐vacancy pairs will change the slope of the curves in the logarithmic resistivity vs. reciprocal temperature plot and the contribution due to di‐solutes will give rise to a non‐linearity of the curves at lower quenching temperatures. The results are discussed in the light of experimental observations.
Infrared Absorption in Heavily Doped n‐Type Si
Authors: Balkanski M. , Aziza A. , Amzallag E. 
Published: July 2007

AbstractTransmission measurements are reported on highly phosphorous‐doped n‐type Si, at three different temperatures 300, 85, and 35°K, and for carrier densities ranging from 6 × 1018 to 4.9 × 1020 cm−3. Below the fundamental energy gap, the data are analysed in terms of three different processes: free carrier absorption, indirect transitions including the phonon contribution as well as the impurity or electron—electron scattering, and interconduction‐band transitions. The absorption band due to inter‐conduction‐band transitions is observed to shift to higher wavelengths, when the doping increases. An explanation is given, taking into account the rise of the Fermi level in the conduction band.
Current Oscillations in GaAs under Acoustic Amplification Conditions. II. Calculation of the Threshold Field
Authors: Hugon P. Leroux 
Published: July 2007

AbstractIn the preceding paperSee this issue, page 331.
, experimental investigations of current oscillations in GaAs are reported. In this paper the conditions of occurrence of a current instability is discussed in the limits of the small‐signal theory. Calculated values of the threshold field and of his variations with the involved parameters are found in agreement with the experiments.
Field‐Ion Microscopic Contrast from Partial Dislocations and Stacking Faults in B.C.C. Metals
Authors: Smith D. A. 
Published: July 2007

AbstractThe geometrical contrast theory of dislocated surfaces is extended to include faults in b.c.c. metals. A general approach to the problem of dislocation and fault contrast is indicated; the characteristic spiral and step configurations from any dislocation and any fault can be deduced from simple crystallographic parameters. In some cases a fault can be characterised completely by noting its line of intersection with an imaged pole and the multiplicity of associated spirals. The limitations of the theory are pointed out.
Grain Growth in Polycrystalline Ice
Authors: Jellinek H. H. G. , Gouda V. K. 
Published: July 2007

AbstractLiterature is not available on the grain growth in polycrystalline ice. The present paper deals with such grain growth in pure ice and ice doped with sodium chloride. The technique consists in measuring grain size distributions as a function of time and deriving the numberaverage equivalent “diameter”, considering the grains as spheres. The functional relationship between the average diameter and time of growth is, for pure and doped ice, of the same form as that found for metals. Arrhenius plots show that the energy of activation is higher for doped ice than for pure ice. The results are discussed in terms of interfacial free energy as being ultimately responsible for grain growth. On a molecular scale, processes take place, which lead to diffusion of units consisting of a number of water molecules across the boundaries.
Polarization Investigations of Localized Exciton States of Doped Benzene Crystals
Authors: Ostapenko I. N. , Shpak M. T. 
Published: July 2007

AbstractThe absorption spectra of localized exciton states of benzene crystals doped with heterocyclic compounds are studied at T = 4.2 °K using polarized light. When the localized level approaches the exciton A‐band edge, the intensity of the localized absorption is shown to increase anomalously in the a‐component and to decrease in the c‐component of the absorption spectrum. Simultaneously the A‐band is partly depolarized and shifts towards the violet side. The experimental results obtained favour certain conclusions about the exciton band structure and the exciton effective mass and are qualitatively interpreted on the basis of current theories of localized states.
An APW Calculation for Silver
Authors: Christensen N. E. 
Published: July 2007

AbstractVarious “muffin tin” potentials have been examined, and a potential leading to a band structure and a Fermi surface in agreement with experiments has been found. This potential is based on relativistic Dirac‐Slater atomic wave functions. In the atomic calculations as well as in the crystal calculations inclusion of full Slater exchange led to the best results. Cyclotron masses, thermal effective mass, optical mass, drift velocities, and group velocities have been calculated.
Tensile Properties of Cu3Au Single Crystals
Authors: Audero M. A. , Victoria M. P. , Vidoz A. E. 
Published: July 2007

AbstractThe tensile properties of ordered and disordered Cu3Au single crystals have been investigated. Measurements have been made to determine the influence of initial orientation of the tensile axis and of the domain size on the work hardening characteristics of Cu3Au. It is shown that the work hardening rate of the ordered crystals increases with the domain size and the occurrence of secondary slip. The nature of the effects is discussed in terms of previous results on Ni3Fe. It is concluded that they can be explained by the antiphase boundary tube mechanism.
Pyroelectric Properties of Rubidium, Cesium, and Thallium Nitrates
Authors: Bury P. C. , McLaren A. C. 
Published: July 2007

AbstractThe pyroelectric properties of single crystals of rubidium, cesium and thallium nitrates have been investigated by direct observation of the dipole moment in an electric field and by measurements of the pyroelectric coefficient (dP/dT) using the Chynoweth technique. These observations have shown that the trigonal forms of these crystals are primary (or secondary) pyroelectrics in which the c‐axis is the polar axis. The Chynoweth technique also indicated the presence of 180° pyroelectric domains which were subsequently revealed by decoration with charged particles from a xerographic developer. Measurements of (dP/dT) versus T have been used to determine the form of the spontaneous polarization as a function of temperature. These results, together with new optical and X‐ray observations, indicate the space group P31 (or P32) for the trigonal form of these crystals, rather than P31 (or P3212) as previously reported on the basis of X‐ray evidence alone.
Zur Theorie der Biexzitonen in monomolekularen Kristallen
Authors: Patzer K. 
Published: July 2007

AbstractEs wird ein Hamiltonoperator hergeleitet, der die Schwierigkeiten beim Übergang von Paulionen zu Bosonen vermeidet und es erlaubt, exakte Gleichungen für die Greenschen Funktionen zu erhalten. Als Spektrum der Biexzitonen wird eine Serie von Energiebändern erhalten. Es wird gezeigt, daß die Bildung von Biexzitonen aus longitudinalen und transversalen Exzitonen unwahrscheinlich ist.
Neutron investigation of the Spin System Dynamics in α‐Cr2O3
Authors: Alikhanov R. A. , Dimitrijević Ž. , Kowalska A. , Kraśnicki S. , Rżany H. , Todorović J. , Wanic A. 
Published: July 2007

AbstractInelastic magnon scattering of neutrons (λ = 1.124 Å) on a single crystal of Cr2O3 at a temperature of 85 °K is investigated by the neutron diffraction technique. The magnon dispersion relation is measured along several tracks in the reciprocal space. A calculated dispersion relation, including four different exchange integrals Ji, is fitted to the experimental results. A good fit is obtained for: J1 = −0.2 meV, J2 = −0.5 meV, J3 = −3.3 meV, and J4 = −7.4 meV.
Creation of U2—F Centre Pairs in U‐Centre Doped KBr Crystals
Authors: Kurz G. 
Published: July 2007

AbstractDetailed measurements have been made on the conversion of U1‐α centre pairs into U2‐F centre pairs in KBr: KH crystals extending the results and suggestions made earlier by Delbecq et al. It is shown that part of the thermally most stable vacancy—interstitial pairs undergo further conversion upon U1 bleaching. Furthermore at 4.5 °K a complete reverse reaction can be induced by bleaching with F light. From these quantitative results the oscillator strength of the U2 band can be determined. A refinement of Delbecq's conversion model is proposed.
The Diffusion of Zn in the III‐V Semiconducting Compounds
Authors: Shaw D. , Showan S. R. 
Published: July 2007

AbstractThe experimental results for chemical and isoconcentration diffusion of Zn in AlSb, GaAs, and GaP have been interpreted using Longini's interstitial/substitutional model. Satisfactory agreement is found with the isoconcentration data if the substitutional Zn is a fully ionized monovalent acceptor and the interstitial is a monovalent donor. The characteristic features of chemical diffusion are explained in terms of a non‐equilibrium situation dominated by the rate of supply of vacancies on the group III sub‐lattice and the flux of interstitial Zn donors. Diffusion‐induced dislocations are assumed to play a major role in the supply of vacancies. Satisfactory qualitative agreement with the chemical diffusion data is found.
On the Orientation Changes during Plastic Deformation of Individual Crystallites in Polycrystalline Aggregates
Authors: Bunge H. J. , Fuchs R. 
Published: July 2007

AbstractThe orientation changes of individual crystallites in aluminium wires were studied during 1% plastic deformation. The crystals near the [111]‐ideal orientation rotated towards this orientation according to the Taylor theory. The crystals of the weak [100]‐texture component showed no resulting rotation component towards [100] in contradiction to the Taylor theory.
Experiments on the Motion of Bubbles in Solids by Sublimation in a Temperature Gradient
Authors: Diez W. , Biersack J. 
Published: July 2007

AbstractThe sublimation mechanism of bubble migration in solids in a temperature gradient has been investigated by microscopic observation of artificial bubbles in ammonium chloride single crystals. The dependence of the bubble velocity on temperature, temperature gradient, and bubble size corresponds with the theory, which takes into account the influence of the evaporation coefficient. Changes in the shape can be understood qualitatively by means of the calculated temperature fields. The shrinking velocity of bubbles, not being in equilibrium of forces, is evaluated and compared with experiments. The polyhedral form of the bubbles and the lenticular shape of pores in UO2 is explained by the low value of the evaporation coefficient for certain crystallographic planes.
Low‐Temperature Lorentz Microscopy on “Weak” Ferromagnetics
Authors: Bostanjoglo O. , Vieweger W. 
Published: July 2007

AbstractMagnetic domains in CrBr3 and CrI3 were investigated down to 3 °K in an electron microscope in the Fresnel and Foucault mode of Lorentz microscopy, and by Fraunhofer diffraction. The experimental domain width was found in agreement with the theoretical value calculated by crystal and magnetic energy considerations. In all modes of Lorentz microscopy the electron optical contrast of the ferromagnetic domains in films with low magnetization and small wall width as occur in CrBr3 and CrI3 is found to deviate markedly from the predictions of the geometric optical theory but is satisfactorily understood by wave optics.
On the Polarization Vectors of Lattice Vibrations
Authors: Grimvall G. 
Published: July 2007

AbstractThe polarization vectors of lattice vibrations in anisotropic crystals of cubic structure are considered from a quantitative point of view. A new anisotropy index A = c11/(c12 + 2c44) is shown to be more adequate as a measure of anisotropy than the conventional s = (c11 — c12)/2c44. The reason for anisotropy is discussed briefly, with special emphasis on simple metals. The approximation of assuming the lattice vibrations to be strictly longitudinal or transverse is discussed for several properties of metals, with sodium taken as an example.
Stray‐Field‐Free Magnetization Configurations
Authors: Hubert A. 
Published: July 2007

AbstractThe concept of stray‐field‐free micromagnetic configurations in applied to Bloch‐ and Néel‐walls, to stripe domains, and to the ripple structure in thin magnetic films. We propose a new structure of Bloch‐walls with a lower energy than the most general classical Bloch‐walls as calculated by LaBonte. In general a stray‐field‐free configuration has a lower symmetry than the simpler structures considered previously. It is concluded that the real structure, if not completely stray‐field‐free, should have at least the same symmetry as a possible stray‐field‐free solution. The significance of Brown's equations, which in general cannot be satisfied without admitting stray‐fields, is analysed with regard to the micromagnetic boundary condition.
Paramagnetic Impurities in Superconductors with Overlapping Energy Bands
Authors: Kon L. Z. , Moskalenko V. A. 
Published: July 2007

AbstractThe influence of paramagnetic impurities on the thermodynamic properties of two‐band superconductors at zero and near zero temperatures is investigated. It is shown that due to interband scattering of electrons there is one gap in two‐band superconductors with impurities. The extreme cases of low and large impurity concentrations are investigated. In the first limiting case an increase in the concentration is accompanied by a linear decrease of order parameters. The expression for the energy gap, densities of states near the energy gap, and the specific heat as functions of impurity concentration are given.
Electric Properties of Dislocations in n‐Type Germanium
Authors: Kryłow J. , Auleytner J. 
Published: July 2007

AbstractOn the basis of the Read theory the position of dislocation acceptor level in n‐type germanium was determined. It amounts to 0.13 to 0.18 eV below the bottom of the conduction band and is independent of the type of introduced dislocations. The influence of the inhomogeneity of deformations and non‐dislocation defects generated in the course of heating and deformation on the precision of determination of the position of dislocation level was taken into account. — Diffusion of impurities was reduced to minimum by covering the samples with tin. A strong effect on non‐dislocation defects generated in the processes of heating and deformation on mobility and magnetoresistance was detected as well as some changes in mobility for the current flow parallel to the direction of dislocation lines.