bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light Effects on Space‐Charge Controlled Currents in CdS
Authors: Bräunlich P. 
Published: July 2007

AbstractThe paper describes two types of light effects on space‐charge controlled currents, both observed in CdS single crystals with In as an injecting and Cu2S as a blocking contact: 1. interaction of optically generated electron‐hole pairs with injected carriers; 2. direct optical excitation of trapped space charge. Photocurrents with a superlinear dependence on voltage have been studied. A new negative photoconductivity effect in CdS is also described and explained by a redistribution process of injected holes and electrons.
Two Beam Kinematical Theory for the Diffraction of Electrons by Crystals with Stacking Faults
Authors: Gevers K. , van Landuyt J. , Amelinckx S. 
Published: July 2007

AbstractThe intensity of weak diffraction spots is calculated on the basis of “a two‐beam kinematic” theory. The assumption is made that apart from the incident beam there is one strongly scattered beam. The incident and the strongly scattered beams are considered to interact according to the dynamic theory, but the dynamic interaction between the strongly and weakly scattered beams is neglected. Expressions are developed for the amplitudes and intensities of the weakly scattered beams both for perfect crystals and for crystal slabs containing stacking faults. The theory leads to the prediction that the dark field image of stacking faults taken in a weak diffraction spot should represent the fringe periodicy characteristic of the strongly diffracted beam. This is confirmed by observations. It is suggested that much weaker fringes with spacing characteristic of the s‐value of the weak spots may be superposed on the strong fringes. These fringes have not been observed.
The Mechanism of Deformation of the Ordered CuAu Alloy
Authors: Syutkina V. I. , Yakovleva E. S. 
Published: July 2007

AbstractElectron microscopy techniques are used to study the domain structure and the mechanism of deformation of the ordered CuAu alloy. Investigations are made into the factors impeding the passage of dislocations across the boundary between domains with differently orientated c‐axes. Experiments indicate that the greatest obstacle to the passage of dislocations across such a boundary is the necessity of pairing single dislocations.
Étude expérimentale de la dynamique des domaines de haut champ électrique dans le couplage électron‐phonon
Authors: Ropé J.‐P. 
Published: July 2007

AbstractNous étudions la répartition de potentiel à l'intérieur des domaines de haut champ électrique qui se propagent dans les échantillons de GaAs présentant des oscillations de courant dues au couplage électron‐phonon. Nous montrons en particulier que le champ électrique dans le domaine augmente lorsque le domaine disparaît.
Relaxation des domaines de haut champ et émission de lumière associées aux oscillations de courant dans GaAs
Authors: Bonnot A. 
Published: July 2007

AbstractUne émission de lumière infrarouge a été observée dans des échantillons d'arséniure de gallium de type n, présentant des instabilités de courant résultant du couplage électro‐acoustique. La lumière apparaît lorsque le domaine de haut champ atteint l'anode de l'échantillon. L'émission de lumière prend naissance quand le champ électrique appliqué est supérieur a un certain champ de seuil E0. L′énergie de la lumière est de 1,42 eV à 77 °K et de 1,36 eV à 300 °K. Ces deux valeurs correspondent à la transition bande à bande du semiconducteur, aux températures considérées. Nous pensons que cette émission est liée à une augmentation du champ dans le domaine pendant sa destruction. Nous montrons que lorsque le domaine disparaît son champ électrique peut effectivement augmenter.
Calculations on the Mechanical Energy of Vacancy Condensation Loops, Stacking Fault Tetrahedra, and Voids
Authors: Sigler J. A. , Kuhlmann‐Wilsdorf D. 
Published: July 2007

AbstractEmploying the most accurate theoretical expressions known for the energy of five different types of vacancy condensation products, the relative stabilities of these are evaluated by means of a B 5500 computer. The calculations are performed for the cases of aluminum, nickel, platinum, copper, gold, and silver, while the defects considered are the hexagonal Frank loop on {111} with 1/3 <111> as Burgers vector, two perfect loops with 1/2 <110> Burgers vectors, one of these being hexagonal on {111} the other diamond‐shaped on {110}, further the spherical void and, finally, the stacking fault tetrahedron. By comparing the results of the calculation with experimental evidence, some broad agreement is found, but also some quite important discrepancies. These are discussed theoretically.
On the Thermal Conductivity of CdTe and Some CdTe1−xSx and CdTe1−xSex Solid Solutions
Authors: Kelemen F. , Néda A. , Niculescu D. , Cruceanu E. 
Published: July 2007

AbstractThe thermal conductivity of CdTe and some solid solutions of CdTe1−x Sx and CdTe1−x Sex (x = 0.1 and 0.2) is studied. Measurements are made at temperatures ranging from 90 to 700 °K, on two kinds of monocrystal specimens, prepared from elements of different purity. In specimens synthetized from less pure elements, the thermal conductivity starts to increase with temperature between 300 and 400 °K, whereas in specimens obtained from elements of 99.9999 per cent purity this increase only occurs at higher temperatures (about 500 °K). The additional thermal conductivity in purer specimens may be ascribed to due to ionization of impurities. For impurities in CdTe, the values of ionization energy calculated from the temperature dependence of the thermal conductivity are comparable with those determined by other methods.
Kinetics of Quenched‐in Vacancies in Pure Platinum
Authors: Polák J. 
Published: July 2007

AbstractThe kinetics of the annealing of vacancies in pure platinum quenched in water is investigated. S‐shaped isothermal annealing curves are observed. After an initial transient region the annealing kinetics is approximately second order. Experimental results are discussed by assuming thermal equilibrium to exist between single‐vacancies and di‐vacancies. By using the deviations from purely second order kinetics, and comparing the calculated and measured values of the effective migration energy, estimates are made of the binding energy of a di‐vacancy B2 = (0.18 ± 0.05) eV and the difference between the migration energy of single and di‐vacancies Δ = (0.34 ± 0.05) eV in platinum.
Crystal Structure and Magnetic Properties of Some Rare Earth Germanides
Authors: Buschow K. H. J. , Fast J. F. 
Published: July 2007

AbstractMagnetic and structural data are determined for eleven rare‐earth germanium compounds with the formula R5Ge3. These compounds are isotypic and have the hexagonal Mn5Si3 type of structure. For R = Pr, Gd, Tb, Dy, Ho, and Er antiferromagnetic behaviour is observed at low temperatures. The antiferromagnetic exchange interaction is weak in these compounds. A field‐induced transition to a magnetic structure with a much higher moment is observed at 4.2 °K for Tb5Ge3, Dy5Ge3, Ho5Ge3 and Er5Ge3. At low temperatures Nd5Ge3 and probably also Ce5Ge3 are ferrimagnetic. The Curie‐Weiss law is obeyed by all these compounds at high temperatures. The observed effective moments are close to those of the free trivalent rare earth ions. La5Ge3 and Y5Ge3 are Pauli paramagnetic.
The Electromagnetic Aspect of Magnetostrictively Induced Torsional Oscillations (the Procopiu Effect with a Cylindrical Ferromagnetic Specimen Fixed at one End)
Authors: Rothenstein B. F. , Policec A. , Lupulescu M. , Anghel C. 
Published: July 2007

AbstractThe Procopiu effect for a cylindrical ferromagnetic specimen fixed at one end, involves the induction of an e.m.f. in a search coil surrounding the specimen when a constant longitudinal magnetic field Hy and an oscillatory circumferential magnetic field Hx are applied simultaneously. It is shown that the shape of the e.m.f. induced in this form of the Procopiu effect differs from that occuring with the same specimen fixed at both ends. Using a constant amplitude for Hx, a study is made of the dependence of the effect upon Hy and upon the phase relations between Hx and the torsional oscillations induced by magnetostriction.
Carrier Recombination in Nickel Doped Germanium from Lifetime and Noise Measurements
Authors: Gouskov L. , Lecoy G. , Llinares C. 
Published: July 2007

AbstractA study is made in order to precise the transition processes for free carriers between the bands and the well‐controlled deep Ni levels in Ge from 100 to 350 °K. The experimental work involves measurements of the lifetime of the photoconductive decay and the generation‐recombination noise.
X‐Ray Diffraction Contrast on Ferromagnetic Domain Walls in Fe‐Si Single Crystals
Authors: Polcarová M. , Kaczér J. 
Published: July 2007

AbstractThe contrast of ferromagnetic domains in (001) Fe‐3% Si single crystal plates is studied using X‐ray diffraction topography. This contrast is found to be due solely to the difference in deformation on opposite sides of the wall which is produced by magnetostriction. 180° walls are therefore never visible, whereas 90° walls show contrast if diffracting planes not belonging to the zone m2 — m2 are used (m1 and m2 are unit vectors parallel to the magnetization on the two sides of the wall).
Der Flußeintritt in Supraleiter II. Art
Authors: Takács S. 
Published: July 2007

AbstractEs wird gezeigt, daß in einem makroskopischen Supraleiter II. Art das Auftreten von Flußwirbeln bereits unterhalb des thermodynamischen kritischen Magnetfeldes energetisch günstig und die “reine” Oberflächenbarriere unwirksam wird. Die Werte für das Entstehungsfeld der Wirbel und für die maximale Eintrittsfeldstärke werden für den Halbraum angegeben; im Anhang werden die maximalen Eintrittsfeldstärken für einen dünnen Hohlzylinder angefügt.
Fatigue Hardening of CuZn Alloys
Authors: Lukáš P. , Klesnil M. 
Published: July 2007

AbstractThe initial stage of the fatigue process — fatigue hardening — is studied for three CuZn alloys with different stacking fault energies in the region of low stress amplitudes (lifetimes of order 105 cycles and higher). The study involves both measurements of the mechanical properties in the microstrain region and transmission electron microscopy. All measurements confirm the strong influence of the stacking fault energy on the course of the hardening. Fatigue hardening arises from both short‐range and long‐range stress fields. The contribution of the long‐range stress fields to the total hardening decreases with decreasing stacking fault energy.
The Band Edge and the Energy Spectrum of In2Se
Authors: Bercha D. M. , Borets A. N. , Stakhyra I. M. , Tovstyuk K. D. 
Published: July 2007

AbstractThe absorption coefficient of In2Se is investigated experimentally near the band edge using polarized radiation. The selection rules for the space group D to which In2Se belongs are determined by group‐theoretical methods. An energy‐band model is proposed which agrees with the experimental data.
Study of Barium Adsorption on Germanium by Field‐Emission Microscopy
Authors: Sokolskaya I. L. , Ivanov V. G. , Fursey G. N. 
Published: July 2007

AbstractThe change in work function of barium‐covered p‐ and n‐type germanium emitters with the degree of coverage θ is investigated by FEM. The curve of work function φ against deposition time is similar to that for barium adsorption on metals. The work functions of clean field‐desorbed surfaces of p‐ and n‐type emitters are determined from the Fowler‐Nordheim slopes with respect to that for barium‐covered surfaces, assuming that the work function of the latter for θ > 1 is φBa = 2.5 eV. The work functions are φp = (4.90 ± 0.05)eV and φn = (4.43 ± 0.05) eV for φp = 3.7 Ωcm and Qn = 2.5 ωmcm, respectively. The difference in the observed work functions compares well with the difference of the Fermi level position. Metallic‐like properties of barium on germanium are observed at coverages θ much less than a monolayer (θ = 0.007).
The Properties of the Low‐Temperature Internal Friction Peak in Silicon
Authors: Khiznichenko L. P. , Kromer P. F. , Kaipnazarov D. K. , Otenyazov E. , Yustpova D. , Zotova L. G. 
Published: July 2007

AbstractThe properties of the low‐temperature internal friction peak are studied in n‐silicon single crystals at a frequency of 100 Hz at a temperature of approximately 110 °K. It is shown that annealing at high temperatures suppresses the peak. Maximum increases after plastic deformation. After γ‐irradiation the peak height is found to decrease with dose by an exponential law. These features suggest that the peak is of the Bordoni‐type. Similar internal friction maxima are also observed in n‐type germanium and p‐type silicon single crystals.
Mikromagnetische Behandlung der Wechselwirkung zwischen Versetzungen und ebenen Blochwänden. II. Anwendungen
Authors: Pfeffer K.‐H. 
Published: July 2007

AbstractEs werden die Änderung der Magnetisierungsverteilung innerhalb und außerhalb der (112)−180°‐Blochwand in Nickel infolge der inneren Spannungen von Einzelversetzungen (Stufen‐ und Schraubenversetzungen), die parallel zur Blochwand verlaufen, und das aus der Spinumordnung resultierende Wechselwirkungspotential zwischen Blochwand und Einzelversetzung berechnet. Die Resultate werden hinsichtlich Größe, Temperaturabhängigkeit und asymptotischem Verhalten mit der Magnetisierungsverteilung und dem Wechselwirkungspotential bei starrem Magnetisierungsverlauf systematisch verglichen. Zur Untersuchung des Einflusses von korrelierten Versetzungsanordnungen auf die Wechselwirkung mit der Blochwand wird die Kraftwirkung von Versetzungsdipolen und Versetzungsgruppen berechnet. Da die aus der Spinumordnung resultierende Wechselwirkung quadratisch von den inneren Spannungen abhängt, ist die von Versetzungsgruppen auf die Blochwand ausgeübte Kraft viel größer, als man bei linearer Superposition der Einzelkräfte erwarten würde. Im Unterschied zu der Kraft, die sich bei Annahme eines starren Magnetisierungsverlaufes berechnet, ist die aus der Spinumordnung resultierende Kraft auch dann noch empfindlich von den Versetzungsabständen abhängig, wenn diese größer als die Blochwanddicke sind.
Zur Theorie der Koerzitivfeldstärke und Anfangssuszeptibilität
Authors: Pfeffer K.‐H. 
Published: July 2007

AbstractMit der Theorie der homogenen Zufallsfunktionen werden unter der Annahme, daß die Ummagnetisierung durch reine 180°‐Blochwand‐Verschiebungen erfolgt, die charakteristischen Größen maxKW(z) und (KWist die Wechselwirkungskraft zwischen einer Blochwand an der Stelle 0 ≦ z ≦L3und Gitterstörungen) und damit die KoerzitivfeldstärkeHcund AnfangssuszeptibilitätXaberechnet. Im Unterschied zu der von Träuble bei der Durchführung der statistischen Analyse der Blochwandbewegung angewandten Theorie der statistisch unabhängigen Zufallsvariablen bedarf dieses Verfahren insbesondere zur Berechnung vonXakeiner besonderer Zusatzannahmen. Die hier dargelegte Theorie gestattet es, den Einfluß beliebiger Versetzungsanordnungen aufHcundXain geschlossener und übersichtlicher Form zu untersuchen. Für Versetzungsanordnungen, die aus Versetzungsschleifen bestehen, die in Lage und Form unkorreliert sind, werden Größe und Temperaturabhängigkeit vonHcundXadiskutiert. Die Korrelationslänge, die ein Maß für das ProduktHcXaist, ergibt sich im Unterschied zu den Resultaten der bisherigen Theorie der Koerzitivfeldstärke und Anfangssuszeptibilität im allgemeinen als verformungsabhängig.
Transport Phenomena in Semiconducting Thin Films
Authors: Tavger B. 
Published: July 2007

AbstractTransport phenomena in thin semiconducting films are studied using the transport equation, the quantization of the transverse motion of the electrons being taken into account. A general formula relating the relaxation time for a thin film to that for the bulk semiconductor is obtained. The mobility is found to increase as the film thickness decreases. Hence the increase of the resistivity with decreasing film thickness does not in general indicate increasing imperfection density. It is found that the Hall constant is only weakly dependent on the film thickness. The transport effects in thin semiconducting films and in bulk semiconductors are compared for several scattering mechanisms.
Waves with Discrete Spectrum in Metals in the Vicinity of the Cyclotron Resonance Frequency
Authors: Blank A. Ya. , Kaner E. A. 
Published: July 2007

AbstractA theoretical study is made of the cyclotron resonance in metals in an inclined magnetic field caused by the existence of the periodical system of high‐frequency current peaks. Weakly damped electromagnetic waves with a discrete spectrum are found near the resonant frequencies. The excitation of waves with a discrete spectrum leads to the fine structure of the cyclotron resonance line.
Impurity Absorption Bands in Thermoluminescent LiF
Authors: Claffy E. W. 
Published: July 2007

AbstractImpurity absorption bands in the ultraviolet (1370 and 1960 Å) and infrared (2.8 μm) which may occur in various commercial crystals of LiF cannot be correlated with the thermoluminescence glowpeak at 210 °C, with the Mg or OH− content, or with each other. The present data fail to support the argument that impurity centers absorbing in the 2000 Å region play an essential role in the thermoluminescence process.
γ‐Irradiation Effect on the Thermal Conductivity of Al2O3 with Cr or Mn Impurities at Low Temperature
Authors: de Goer A. M. , Dreyfus B. 
Published: July 2007

AbstractThe effect of γ‐irradiation on the thermal conductivity of samples of Mn or Cr‐doped Al2O3 is measured between 1.3 and 300 °K. Ions with an even number of electrons (particularly those with the Mn3+ configuration) are much more effective in scattering phonons than Kramers' ions. Comparison of the experimental data therefore strongly suggests the presence of Cr2+, isoelectronic of Mn3+, in irradiated ruby. A preliminary study of the thermal annealing shows that the recovery of the thermal conductivity is rather complicated.
Zur Versetzungsanordnung in dünnen, durch Kristallisation gewonnenen Germanium‐Folien
Authors: Paschoff N. , Heydenreich J. 
Published: July 2007

AbstractDurch Kristallisation aus der Schmelze hergestellte dünne Germanium‐Folien werden elektronenmikroskopisch in Durchstrahlung untersucht. Typisch für die ‐ meistens in 〈111〉‐Orientierung vorliegenden ‐ Folienbereiche ist das Vorhandensein relativ geradlinig in 〈112〉‐Richtung verlaufenden 30°‐Versetzungen und in 〈110〉‐Richtung liegender 60°‐Versetzungen. Eine Modellvorstellung für die Entstehung einer aus parallelen, in 〈112〉‐Richtung verlaufenden Versetzungen bestehenden Versetzungsanordnung wird vorgeschlagen. Einige Beispiele für die Wechselwirkung von Versetzungen auf der Grundlage eines „super kink”︁‐Modells werden hervorgehoben.
Dielectric Properties of Interstitial Impurity Cations in Alkali Halide Crystals
Authors: Lal K. 
Published: July 2007

AbstractThe dielectric behaviour of an interstitial divalent impurity cation associated with cation vacancies in alkali halide crystals is investigated. Two cases are considered: In the first case the two cation vacancies are assumed to be at the nearest neighbour positions. In the second case the impurity is assumed to be attached to one vacancy at a second nearest neighbour position. The impurity‐vacancy dipoles show relaxational losses, which reach a maximum at 4 ω1 in the first case and at ω1 in the second case. Here ω1, is the jump frequency of the vacancy between lattice sites. The maximum values of the loss tangent are calculated for the two cases and compared with that obtained for the case of a substitutional impurity associated with one vacancy at a nearest neighbour position.
Investigation of the Thermal Conductivity of InSb‐GaSb Solid Solutions
Authors: Zeinalov S. A. , Aliev M. I. 
Published: July 2007

AbstractResults of a thermal conductivity study on InSb‐GaSb solid solutions are presented for the entire solubility range of 80 to 500 °K. It is shown that the thermal conductivity is mainly due to the lattice. Up to a certain temperature three‐phonon processes are prevalent in all the solid solution samples. In alloys near the equimolar composition the lattice thermal resistance does not depend on T. This is due to the limitation of the phonon mean free path by the random structure of the alloy and by heat transfer through the quantum exchange of energy between the neighbouring atoms of the lattice.
Luminescence and Photoconductivity of the B‐Centre in Additively Coloured KCl:Ag Crystals
Authors: Degrieck W. , Jacobs G. 
Published: July 2007

AbstractThe luminescent and photoconductive properties of the complex B‐band in additively coloured KCl: Ag are investigated in the temperature range between 300 °K and liquid helium temperature. A mechanism is proposed to account for the absence of low temperature fluorescence and the parallel occurrence of photoconductivity and luminescence at higher temperatures. The experimental data are discussed on the basis of a configuration coordinate diagram.
Optical Absorption in Electric and Magnetic Fields
Authors: Spector H. N. 
Published: July 2007

AbstractThe theory of optical absorption in electric and magnetic fields is extended to treat the case where the relative orientation of the fields is arbitrary. The treatment is valid within the limits of the effective mass approximation. For the cases where one of the fields is absent or where the electric and magnetic fields are perpendicular to each other, the theory yields the results previously derived. However, for the case of parallel magnetic and electric fields, the theory yields the result that the absorption edges and peaks are broadened due to the field induced tunneling between the bands. The effect of the parallel fields on phonon‐assisted transitions is also calculated. It is found that steps in the optical absorption which normally occur are broadened due to the field induced tunneling.
Variations of Young's Modulus throughout the Mixed State in Niobium
Authors: Kramer E. J. , Bauer Ch. L. 
Published: July 2007

AbstractVariations of Young's modulus throughout the mixed state in niobium have been measured as a function of external magnetic field. The variations then are converted to magnetization values utilizing the two‐phase model of the mixed state. Results are in satisfactory agreement with the measured magnetization curve, and thus support the applicability of the two‐phase model.
On the Isotope Effect in Interstitial Diffusion
Authors: Pegel B. 
Published: July 2007

AbstractFollowing an idea of Prigogine and Bak the frequency factor of interstitial diffusion is calculated for a classical, one‐dimensional model of a crystal. An isotope effect is found which is more complicated than that obtained from rate theory. This effect depends very strongly on the lattice spectrum. The model explains qualitatively recent experimental observations on the isotope effect.
Colour Centres in Ruby Crystals
Authors: Arkhangelskii G. K. , Morgenshtern Z. L. , Neustruev V. B. 
Published: July 2007

AbstractAn investigation is made of the absorption spectra, the spectral dependence of the luminescence quantum output, glow curves, and the radiation spectra of the glow curves of ruby crystals. These crystals are coloured by intense light flashes or by γ‐rays from Co60. It is found that the absorption is greater in coloured crystals while the luminescence quantum output is smaller. The thermal decoloration of crystals is accompanied by a luminescence in the R‐line region. A decrease in the Cr3+ ion concentration is detected in coloured crystals by ESR measurements. The similarity of all the characteristics obtained allows a conclusion about the identity of the colour centres arising under optical and γ‐irradiation of the crystals. The results obtained here and published data suggest that Cr2+ and Cr4+ act as colour centres, and that their formation under optical coloration is duo to Cr3+ ion ionization via a two‐step process. It is shown that the gradual increase of the ruby generation threshold observed experimentally, which gives laser operation, is due to the formation of colour centres which cause a parasitic absorption of the pumping light.