bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dislocation Geometry of Crystalline Mercury
Authors: Heckscher F. , Crocker A. G. 
Published: July 2007

AbstractThe predominant slip direction of crystalline mercury is not the closest‐packed direction. In order to explain this and related observations, a geometrical analysis has been made of the types of dislocation which may be present in the mercury structure. Two approaches have been adopted. The first of these is based on the well‐established dislocation geometry of face‐centred cubic crystals; it does not lead to an adequate understanding of the experimental results. A satisfactory explanation of the observations is obtained, however, in the second approach, which considers the stacking sequence of the mercury slip planes. Some general implications of the results are discussed.
Étude de l'effet „laser”︁ dans des jonctions d'antimoniure de gallium
Authors: Chipaux C. , Eymard R. 
Published: July 2007

AbstractL'étude du rayonnement émis par des jonctions d'antimoniure de gallium tirées, polarisées dans le sens direct, nous a permis d'observer l'effet „laser”︁ pour nombre d'entre elles. Pour une de ces diodes, il a été possible de mettre en évidence a 78 °K une structure de modes normaux, dont l'écart correspond a n − ≈ 4. Cette jonction a montré l'effet „laser”︁ en régime continu, à 5 °K, pour une densité de courant injecté de 300 A/cm2. L'emploi d'un tube convertisseur d'images a permis d'observer l'émission filamentaire en régime „laser”︁. L'énergie des photons émis est, suivant les diodes, 775, 790 ou 800 meV a 78 °K. L'une des jonctions présente l'effet “laser” simultanément sur 790 et 800 meV.
Effet d'une induction magnétique sur l'échauffement des porteurs dans InSb
Authors: Buchy F. 
Published: July 2007

AbstractNous avons effectué des mesures de résistivité en présence d'électrons chauds dans l'antimoniure d'indium à 78 °K. L'échantillon était placé dans une induction magnétique transversale. Les résultats obtenus peuvent être expliqués par la présence simultanée de plusieurs mécanismes de diffusion, à savoir: phonons optiques polaires, impuretés ionisées, et phonons acoustiques, à condition d'utiliser la récente valeur de 30 eV pour le potentiel de déformation suggérée par Haga et Kimura. Nous avons également mis en évidence deux effets quantiques que les théories actuelles n'expliquent pas.
Colour Centres in Alkaline Earth Fluorides
Authors: Feltham P. , Andrews I. 
Published: July 2007

AbstractThe effect of trace elements on the optical and UV absorption of X‐irradiated calcium fluoride crystals was investigated. Crystals displaying the oxygen cut‐off at about 220 nm in the unirradiated state yielded the α and β absorption bands at about 375 and 550 nm, respectively. In the absence of the cut‐off the well known four‐band spectrum (225, 335, 400, and 580 nm) appeared. This was not significantly influenced by the level of cation impurities, including yttrium in amounts of 0.5 to 1000 ppm. A possible relation between the two spectra is suggested. An attempt was made to locate the F‐band by evaluating the 1‐2p transition energy of electrons trapped at vacant fluorine sites, and the calculations were extended to the fluorides of strontium and barium. The calculated absorption wavelengths for CaF2 (400 nm) and BaF2 (610 nm) are reasonably close to those of 375 and 660 nm ascribed by Arends to F‐centers on the basis of his ESR data. The value derived for SrF2 (495 nm) suggests that the strongest peak, occurring close to 450 nm in additively coloured crystals, corresponds to the F‐centre. The origin of a ‘Mollwo’ relation satisfied by the bands of these crystals, is discussed.
Zum Kristallisationsverhalten von Selenaufdampfschichten
Authors: Peibst H. , Ammon G. 
Published: July 2007

AbstractEs wurden Aufdampfversuche mit unterschiedlich thermisch vorbehandelten Selenproben durchgeführt. Röntgenographische Texturuntersuchungen und elektronenmikroskopische Aufnahmen der Aufdampfschichten erbrachten den Beweis, daß das Kristallisationsverhalten von Selen durch eine thermische Vorbehandlung des Materials beeinflußt werden kann.
Untersuchung des Rauschspektrums von CdS‐Einkristallen
Authors: Rohde H. J. , Marz M. 
Published: July 2007

AbstractDas elektronische Rauschen von CdS‐Einkristallen wurde in einem einfachen Hafttermmodell diskutiert und im Frequenzbereich 20 Hz bis 500 kHz gemessen. Es wird eine Methode angegeben, mit der aus dem Generations‐Rekombinationsrauschen energetische Lage, Frequenzfaktor und Einfangquerschnitt flacher Haftstellen bestimmt werden können. Für diskrete Terme, die 0,3 bis 0,6 eV unter dem Leitungsband liegen, werden Frequenzfaktoren von etwa 1010 bis 1011 s−1 und Einfangquerschnitte von 10−15 bis 10−16 cm2 ermittelt. Die Ergebnisse werden mit aus Leitfähigkeitsglowkurven gewonnen Werten verglichen. Ferner wurden der Einfluß einer Hafttermverteilung und einer Majoritätsträgerinjektion auf das Rauschspektrum untersucht. Aus dem Schrotrauschen wurde die Driftbeweglichkeit freier Leitungselektronen bestimmt. Es ergeben sich Werte zwischen 30 und 50 cm2V−1s−1 bei Zimmertemperatur.
Zur Theorie des Photoeffekts an p‐n‐Übergängen bei ungleichen Lebensdauern der Minoritäts‐ und Majoritätsträger
Authors: Diehl H. 
Published: July 2007

AbstractWir untersuchen den Einfluß ungleicher Lebensdauern der Minoritäts‐ und Majoritätsträger auf die Photospannung an p–n‐Übergängen. Die Rechnung liefert einen geschlossenen Ausdruck, der unmittelbar diskutiert werden kann. Im Gültigkeitsbereich der Ausgangsgleichungen gibt es keine Sättigung der Photospannung.
Plastic Deformation of CsI Single Crystals
Authors: Urusovskaya A. A. , Thyagarajan R. 
Published: July 2007

AbstractThe plastic deformation of CsI single crystals by compression is studied. Different regions of the stress‐strain curve are compared with the distribution of birefrigence bands along slip lines and with the arrangement of dislocation etch pits. The various stages of uniform deformation and of kink‐band formation are considered in detail. It is found that both diffusion and slipping processes occur, even during linear work hardening, and this leads to polygonisation. After the kink‐band formation stage not only polygonisation, but also recrystallisation is observed, which indicates an increase in the diffusion process.
X‐Ray Diffraction from Deformed Cerium: Effects due to Extrinsic Stacking Faults
Authors: Otte H. M. , Chessin H. 
Published: July 2007

AbstractPreliminary measurements of the peak shifts in the X‐ray powder pattern of cerium cold‐worked by filing at room temperature are reported. Because cerium oxidizes rapidly in the atmosphere, the experimental procedure is more complicated than that usually followed in the preparation of cold‐worked metal filings for the measurement of intrinsic faults. The preliminary data on cold‐worked cerium, although of lower accuracy than that normally attainable in this type of work, nevertheless showed peak displacements in the Debye‐Scherrer pattern that were in most cases in the direction theoretically predicted for relatively low probabilities of extrinsic stacking faults. A more detailed investigation is required to verify the line broadening and asymmetry effects produced in the line profiles. The observations were complicated by an apparent annealing out of the peak shifts at room temperature although the increased (extrapolated) lattice parameter remained.
On the Theory of Interband Magneto‐Dispersion Effects in Semiconductors
Authors: Uritsky S. I. , Shuster G. V. 
Published: July 2007

AbstractMagneto‐dispersion effects in crossed fields are considered, expressions being obtained for the Faraday and Voigt effects. It is shown that the electric field displaces the peaks in the long wave region and gives rise to additional resonance peaks.
Anomalous Transmission of X‐Rays in Fe‐3 pct Si Crystals and the Observation of Ferromagnetic Domains
Authors: Roessler B. , Kramer J. J. , Kuriyama M. 
Published: July 2007

AbstractCrystals of an iron ‐ 3 pct silicon alloy were grown by the surface energy induced secondary recrystallization technique. These crystals, which were 0.006 to 0.012 in. thick and had a {100} surface, were found to anomalously transmit X‐rays, revealing both dislocations and ferromagnetic domains along 〈100〉 directions. The domain structure disappeared in the presence of a magnetic field, and reappeared when the field was removed.
Propriétés électriques des solutions solides bismuth‐antimoine
Authors: Dugué M. 
Published: July 2007

AbstractDes monocristaux homogènes d'alliages bismuth‐antimoine contenant jusqu'à 15% d'antimoine ont été préparés. Des mesures de résistivité, des coefficients galvanomagnétiques ont été faites sur ces alliages en fonction de la température entre 14 et 300 °K. La variation du paramètre cristallin c et celle de la largeur de bande interdite en fonction de la concentration en antimoine ont été précisées. Le comportement “anormal” des coefficients galvanomagnétiques rend difficile l'interprétation des résultats.
Electron Motion in Metals with Helicoidal Spin Arrangements
Authors: Vertogen G. , Caspers W. J. , Dekker A. J. 
Published: July 2007

AbstractBy assuming that the magnetic structure of metals with helicoidal spin arrangements fits the crystallographic structure, solutions of the Schrödinger equation are obtained which are plane waves modulated by a function with the periodicity of the magnetic structure. The solutions show that in general depolarization of the conduction electrons will occur, i.e. the spin will not be a good quantum number. The depolarization is also shown to occur for a simple conduction band by treating the interaction between the spin of the electron and the spin of the magnetic ions as a perturbation.
Der Einfluß von Übergangselementen auf die Thermospannung von Reinstkupfer
Authors: Richter F. 
Published: July 2007

AbstractEs wird über die Änderung der differentiellen und integralen Thermospannung von reinem Kupfer (99,9997%) durch das Zulegieren der Elemente, Titan Vanadin, Chrom Mangan, Eisen, Kobalt, Nickel, Palladium, Platin, Zink und Gallium im Temperaturbereich von —180 bis 200 °C berichtet. Von jedem Zweistoffsystem standen je drei Proben mit verschiedenen Legierungsgehalten zwischen 0,05 und 3 At.% zur Verfügung. Trägt man die Änderung der Thermospannung gegenüber den zulegierten Elementen auf, so erhält man beim Chrom und beim Eisen je ein Minimum, wobei das letztere sich bei zunehmender Temperatur zum Kobalt verschiebt.Das Auftreten der beiden Extrema wird nach Friedel durch die Streuung der Leitungselektronen an virtuellen d‐Zuständen der Legierungsatome erklärt, wobei die beiden Minima auf die Aufspaltung der 5 d‐Zustände in zwei mit entgegengesetzter Spineinstellung schließen lassen.
Die “kritische Wachstumsgeschwindigkeit” realer Kristallflächen in Lösung und ihre Abhängigkeit von Störungen des Keimes
Authors: Gülzow G. , Gülzow Hj. , Lüdke W. 
Published: July 2007

AbstractEs wird über Auswirkungen von Störungen des Keimes auf den Realbau der in Lösung gezüchteten Kristalle berichtet und nachgewiesen, daß im Keim vorhandene Baufehler sich in den wachsenden Kristall als primäre Störungen fortpflanzen. Die Versuche zeigen, daß jede Fläche eines Realkristalls eine für sie spezifische “kritische Wachstumsgeschwindigkeit” besitzt, die vom Störungsgrad der Oberfläche der betreffenden Kristallart abhängt. Bei Überschreitung dieses Wertes entwickeln sich in der Umgebung der primären Störungen zahlreiche Einschlußhohlräume zu sekundären Störungen. Die aus diesem Verhalten not‐wendigen Schlußfolgerungen bei der Züchtung von Kristallen werden diskutiert.
Epitaxiales Wachstum von Silbersulfid auf dünnen Silberschichten
Authors: Schlötterer H. 
Published: July 2007

AbstractAuf Steinsalzspaltflächen aufgedampfte Silberschichten wurden mit Schwefelwasserstoffgas behandelt, Hierdurch bildet sich Silbersulfid mit der monoklinen Elementarzelle des Akanthits. Silber und Silbersulfidschichten zusammen wurden mit dem Elektronenmikroskop und mit Elektronenbeugung untersucht. Die Silbersulfidkristalle sind epitaxial zu den Silberschichten aufgewachsen. Es treten zwei verschiedene Kristallgruppen auf, die sich äußerlich durch die Richtungen ihrer Seiten unterscheiden, nämlich 〈110〉‐ und 〈100〉‐ Kristalle, Gemeinsam ist den acht verschiedenen Sulfid‐Orientierungen, daß die (012)‐Ebene der Ag2S‐Kristalle nahezu parallel zur (001)‐Ebene des Silbers verläuft. Die acht Orientierungen lassen sich durch Drehungen um 45° bzw. 90° oder durch Spiegelung an einer {220}Ag‐Ebene (Zwillingsebene) ineinander überführen. Bei einigen 〈100〉‐Kristallen werden Versetzungsanordnungen beobachtet, die auf die von van der Merwe für epitaxiale Schichten vorhergesagten Grenzflächenversetzungen schließen lassen.
Dimensional and X‐Ray Diffraction Changes in Irradiated Single Crystal BeO
Authors: Austerman S. B. , Miller K. T. 
Published: July 2007

AbstractSingle crystals of BeO were irradiated by high energy (≧ 1 MeV) neutrons to doses of 1020 to 6 × 1020 nvt at low temperature (< 100 °C). The crystal structure effects of irradiation were examined by X‐ray diffraction and measurement of interfacial angles between crystallographic faces. The diffraction patterns are characterized by duplex reflections each composed of a sharp and a broad component. The sharp component is attributed to the matrix crystal volume, which is expanded by a random distribution of point defects. The broad component is attributed to the presence of interplanar clusters lying parallel to the basal plane. This structure showed little change below 800 °C with short‐term anneal. Between 800 and 1600 °C there was nearly complete recovering of line breadth and lattice constants. The annealing data indicate (1) removal of the point defects, and (2) some growth of cluster size, during thermal annealing.
Recombinaison radiative dans le germanium fortement dopé et compensé
Authors: La Guillaume C. Benoità , Cernogora J. 
Published: July 2007

AbstractL'étude da la photoluminescence de Ge dégénéré et compensé montre que la raie d'émission á basse température se déplace vers les hautes énergies avec le niveau d'excitation, ce qui permet de mettre en évidence les queues de densité d'état.
Die Orientierungs‐ und Verformungsabhängigkeit der reversiblen Suszeptibilität von Nickeleinkristallen
Authors: Mehrer H. , Kronmüller H. , Seeger A. 
Published: July 2007

AbstractAn Nickeleinkristallen wurde bei Raumtemperatur die reversible Suszeptibilität verschieden orientierter Proben in Abhängigkeit vom äußeren Magnetfeld Ha gemessen. Bei unverformten Proben (mit Ausnahme der 〈111〉Kristalle) sind drei Feldstärkebereiche zu unterscheiden, denen jeweils ein bestimmter Magnetisierungsprozeß zugeordnet werden kann. Irreversible Blochwandverschiebungen haben in Feldern bis ca. 15 Oe eine starke Abnahme der reversiblen Suszeptibilität zur Folge. Drehungen gegen die Kristallenergie sind in einem mittleren Feldstärkebereich die Ursache für die Magnetisierungszunahme. Dieser Bereich wird abgelöst durch den Bereich der Einmündung in die Sättigung.Messungen der reversiblen Suszeptibilität an verformten Proben gestatten es, den Einfluß der plastischen Verformung auf die verschiedenen Magnetisierungsprozesse zu untersuchen.
The Interaction Between Anti‐Ferromagnetic Domain Walls and Dislocations in Nickel Oxide as Observed in the Electron Microscope
Authors: Remaut G. , Delavignette P. , Lagasse A. , Amelinckx S. 
Published: July 2007

AbstractSome further electron‐microscope observations are reported of anti‐ferromagnetic domain walls in NiO. The thin foils used here are less perfect, and have a larger density of dislocations, than those used in the earlier work. This allows the observation of the interaction between dislocations and domain walls. The peculiarities and the origin of this interaction are discussed.
Investigation of the External Photoelectric Effect in HgTe
Authors: Wojas J. 
Published: July 2007

AbstractResults are presented of investigations on the external photoelectric effect in HgTe samples containing a few monocrystalline grains. The investigations use the retarding field method in a spherical vacuum condenser. Monochromatic light of wavelengths 2537 and 2480 Å is used for excitation and the current‐voltage characteristics are measured. Both newly split surfaces and surfaces which have been subjected to mechanical treatment are examined. Mean values of the thermoelectric and photoelectric work function are measured and found to be respectively: (4.120 ± 0.005) eV and (4.130 ± 0.005) eV. Values of the absolute quantum yield for samples at λ = 2537 Å are within the range 1.58 × 10−7 to 6.9 × 10−6 electrons/quantum. Changes are observed in the photoelectric characteristics of surfaces exposed to air for a period of time. The concentration of electrons and holes in the samples and the effective mass ratio mh/me are computed for energy gaps of +0.01, 0, and −0.01 eV.
Nonlinear Electrical Effects and Recombination of the Hot Electrons in Compensated Germanium
Authors: Kagan M. S. , Kalashnikov S. G. , Zhdanova N. G. 
Published: July 2007

AbstractSteady state and transient current‐voltage characteristics are studied for Cu‐doped n‐type Ge samples with the upper Cu level (Ec — 0.26) eV partly compensated. The field strength is varied from ∼ 1 V/cm to 104 V/cm. The I‐U curves obtained are sublinear at field strengths above ∼ 100 V/cm. A study is made of the effect of temperature and of the spectrum of the incident light upon both the steady state and the kinetics of the photocurrent. Negative differential conductivity and coherent low frequency oscillations are observed at nitrogen temperatures with high illumination. The nonlinear effects are shown to be due mainly to the reduction of electron concentration in the conduction band. This could be ascribed to the field dependence of α the probability of electron capture by the doubly charged Cu ions. In the strong electric fields the crystals are becoming inhomogeneous due to the formation of strong‐ and weak‐field regions. The possible influence of these inhomogenities on the nonlinear effects is discussed and the change of α in the strong field is estimated.
On the Theory of Transport Phenomena in Low Mobility Crystals (I)
Authors: Klinger M. I. 
Published: July 2007

AbstractPrevious theory [9] is developed to give a simple and sufficient general method of calculating transport coefficients in low mobility solids. The current is considered to be carried either by small polarons or by such type carriers (in the condon type cases [4]). Formulae for the mobility tensor and thermoelectric coefficients are derived and discussed.
Photon‐Induced Reorientation of M‐Centers in Potassium Chloride
Authors: Turner T. J. , De Batist R. , Haven Y. 
Published: July 2007

AbstractThe reorientation of M‐centers in additively colored KCl crystals, due to the absorption of polarized F‐light is studied experimentally. The time dependence of the resulting dichroism can be described by either one, or two relaxation times, depending upon the geometry. This agrees with the theoretical predictions of a previous paper [21]. From the values of the relaxation times obtained at 200 °K, it is concluded that absorption of MF [001] photons induces a rotation of the M‐center with a quantum efficiency which is approximately three times as large as that associated with absorption of MF [011] photons. The temperature dependence of the quantum efficiency for the process can be described by an activation energy of a few hundredths of an eV.
Tracer Diffusion in β‐Titanium
Authors: Askill J. , Gibbs G. B. 
Published: July 2007

AbstractTracer diffusion measurements in β‐titanium are reviewed and new data presented for solutes Sc46, Sn113, and P32. All Arrhenius plots are curved and give unusually low activation energies and frequency factors. Various explanations are outlined and it is suggested that monovacancy diffusion dominates but that divacancy contributions may become appreciable near the melting point. Impurity activation energies and diffusion rates are closely related to atomic size and compressibility.
Volumenselbstdiffusion in polykristallinem Antimon
Authors: Hässner A. , Hässner R. 
Published: July 2007

AbstractDie Volumenselbstdiffusion in polykristallinem Antimon wurde im Temperaturbereich 384 bis 583 °C mit der Restaktivitätsmethode untersucht. Zwischen 473 und 583 °C kann die Temperaturabhängigkeit des SDK durch folgende Parameter charakterisiert werden: D0 = 1,05 cm2/s, Q = (39,5 ± 1,4) kcal/mol. Die Werte stimmen im wesentlichen mit Angaben von Huntington und Mitarbeitern überein. In der Diskussion wird das anomale Selbstdiffusionsverhalten von Antimon sowie anderer Elemente der Klassen II und III behandelt.
Effects of Dilute Rare‐Earth Additions on the Electrical Conductivity of Cerium at Low Temperatures
Authors: Clinard F. W. , Elliott R. O. , Miner W. N. 
Published: July 2007

AbstractTwo atomic percent of the various trivalent rare earths were dissolved in cerium, and the electrical resistivities of these dilute binary alloys evaluated in the range 1.5 to 297 °K in order to determine whether the various solute magnetic properties might be reflected in resistivity measurements. The γ and β‐cerium phases at room temperature showed a roughly linear dependence of resistivity on atomic number of the rare‐earth solute, noted was a slight effect attributed to solvent‐solute atomic size mismatch. At 4 °K the resistivities of predominantly α phases were found to be influenced by small amounts of β, and predominantly β phases by small amounts of α. Spin‐disorder resistivities for the β phase of the various alloys did not reflect the influence of any solute magnetic parameters, but did decrease slightly in the direction of the heavier rare‐earth solutes.
Magnetic After‐Effects in Iron‐Rich Ferrites Containing Vacancies
Authors: Braginski A. 
Published: July 2007

AbstractThree ionic‐migration magnetic after‐effects are considered on the basis of a Fe2+‐ion anisotropy model. These effects occur in magnetite, and in iron‐rich ferrites containing vacancies. A brief survey of experimental data is given. Results are quoted for temperature spectra of disaccommodation, domain‐wall stabilization in polycrystalline samples, and induced anisotropy relaxation in single crystals. All three effects can be ascribed, by using Slonczewski's theory, to the Fe2+ anisotropic interaction with the spontaneous magnetization in a spinel lattice. It is believed that this interaction causes migration of single Fe2+‐ions, and of Fe2+ — Fe2+ pairs, through intermediary single vacancies. Satisfactory qualitative agreement is found between the experimental results and the proposed model.
Electronic Attenuation of Longitudinal Soundwaves in Aluminium
Authors: Berre B. , Olsen T. 
Published: July 2007

AbstractThe frequency dependence of the difference between the attenuation of longitudinal soundwaves in a perpendicular magnetic field and in zero field is used in an experimental analysis of three parameters in the electron‐phonon interaction. The parameters are the electron mean free path and the magnitude of the interaction in zero and infinite field. The first parameter is compared with the mean free path deduced from electrical size effects. The interaction parameter in zero field is found to be in fair agreement with theoretical estimates. In high fields the interaction is not localized at the fermi surface, and it is found that symmetrically shaped orbits having an electron group velocity normal to the magnetic field, contribute most strongly to the attenuation.
The Determination of the Bond Energies in the Alloy System Au‐Cu
Authors: Zsoldos L. 
Published: July 2007

AbstractThe various bond energies are calculated from the heats of formation, using the basic assumption that the energies vary quadratically with small variations of the nearest‐neighbour distance. The ordering‐energies in AuCu3 and Au3Cu alloys are found to be 0.0486 and 0.0396 eV, respectively.