bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Absorption Band Grown in Thermally Bleached Neutron‐Irradiated Lithium Fluoride
Authors: Kamikawa T. , Kazumata Y. , Ozawa K. 
Published: July 2007

AbstractAn absorption band having a maximum at 630 nm is observed in neutron irradiated “pure” LiF crystals which have been thermally bleached and aged. The properties of this band are studied, and its origin is discussed.
Two‐Particle Green's Function Method in the Theory of Light Absorption by Impurity Centres in Solids
Authors: Lubchenko A. F. , Dudkin S. I. 
Published: July 2007

AbstractA two‐particle Green's function method is used to calculate the dispersion and absorption of light by impurity centres in solids, assuming the electron‐level separation to be of the same order of magnitude as the maximum phonon energy and assuming a weak electronphonon interaction. The absorption spectrum and corresponding dispersion curve are shown to contain phonon and non‐phonon contributions. The forms of these contributions are calculated and their variation with temperature and the electronic structure of the impurity centre is investigated.
Investigation of Gold Doped Germanium in High Electric Fields
Authors: Sondaevskii V. P. , Karakushan E. I. , Stafeev V. I. 
Published: July 2007

AbstractCurrent voltage characteristics of n‐type Ge diodes with an incompletely filled Au level at 0.2 eV are investigated at liquid nitrogen temperature. The current voltage dependence exhibits three stable regions, denoted by “a”, “b”, and the high current region. Region “a” is only stable at low voltages where the capture cross section is independent on electric field strength. Transition from region “a” to “b” is due to a field induced electron capture by the 0.2 eV level at higher voltages. At sufficiently high currents hole injection begins to play the predominant role, and the characteristic becomes S‐type. The intermediate regions between the stable ones are characterized by large current and voltage oscillations.
Two‐Stage Excitation of the Phosphorescence of Ruby
Authors: Morgenshtern Z. L. , Neustruev V. B. 
Published: July 2007

AbstractA long‐time phosphorescence of ruby is found under intense optical excitation in the spectral region of the R‐lines. From the initial brightness decay, as a function of the intensity and wavelength of the exciting light, it is suggested that the phosphorescence has a recombination character. The long‐wavelength limit of excitation corresponds to about 2 eV. These results indicate a complex character for the phosphorescence excitation (two‐photon or two‐step). To differentiate between these two possibilities experiments are performed using two excitation pulses with various time delays between them. These experiments show that two‐step excitation of electrons into the conduction band of ruby takes place over 2E levels of the Cr ions. From the results, and absorption data of ruby and corundum, a band scheme is proposed which explains the long‐wavelength limit of phosphorescence excitation in terms of indirect transitions.
On the Use of Thiele's Semi‐Invariants in Ferromagnetism
Authors: Ferris‐Prabhu A. V. M. 
Published: July 2007

AbstractThe semi‐invariants of Thiele are used to calculate the effect of the kinematical interactions on the temperature dependence of the magnetization on the spinwave model of ferromagnetism. It is first assumed that the only effect is to restrict the spinwave eigenvalue spectrum to 2 S. The semi‐invariants are calculated exactly and an expression is obtained for the magnetization which contains only half odd integer powers of T. The coefficients contain the factor 1–(1 + 2 S)−n/2 and as S → ∞ reduce to Dyson's coefficients. Next the interaction of the spinwaves is specifically included. The first three semi‐invariants are calculated exactly. A conjecture is made as to the form of the first order term of the n‐th semi‐invariant from which the magnetization is calculated. The expression bears an interesting resemblance to Watson's generalized integral.
E. P. R.‐Studies of V2O5 Single Crystals. I. Defect Centres in Pure, Non‐stoichiometric Vanadium Pentoxide
Authors: Gillis E. , Boesman E. 
Published: July 2007

AbstractThe E.P.R.‐spectra of zone‐refined V2O5 are interpreted in terms of a defect centre consisting of an unpaired electron interacting with two equivalent vanadium nuclei separated by an oxygen vacancy. This conception leads to the establishment of a defect formula for V2O5, involving V4+ and V3+ ions. A self‐consistent mechanism is proposed for the formation of the low‐temperature form of non‐stoichiometry in V2O5. Principal values of the approximately axially‐symmetric spin‐Hamiltonian are
E. P. R.‐Studies of V2O5 Single Crystals. II. Defect Centres in Molybdenum‐Doped Vanadium Pentoxide
Authors: Boesman E. , Gillis E. 
Published: July 2007

AbstractIn Mo‐doped V2O5 a paramagnetic defect is formed, in which the unpaired spin interacts with only one vanadium nucleus. Two non‐equivalent centres are present per unit cell. Both have the c‐axis as the principal axis of the g‐and hyperfine tensor, whereas one of the other axes forms an angle of ±7° with b‐axis. The results are summarized by an orthorhombic spin‐Hamiltonian with

Some possible models are discussed.
Temperaturabhängigkeit des Photoeffekts von anodisch hergestellten ZrO2‐Schichten
Authors: Hartl M. , Achtziger K. 
Published: July 2007

AbstractDas photoelektrische Verhalten ohne angelegte Spannung bei Bestrahlung mit UV‐Licht wurde an anodisch oxydierten und metallkontaktierten Zr‐Blechen als Funktion der Temperatur im Bereich von +25°C bis −150°C bei Oxyddicken zwischen 75 und 1500 Å gemessen. Der Photokurzschlußstrom zeigt mit fallender Temperatur eine starke Abnahme, welche mit zunehmender Oxyddicke ausgeprägter wird und sich einer e‐Funktion nähert. Als Erklärung wird eine gleichlaufende Temperaturabhängigkeit der Diffusionslänge der vom Licht angeregten und durch einen Potentialgradienten im Oxyd getrennten Ladungsträger angenommen. Die Photospannung dagegen ist bei dünnen Schichten (≦ 500 Å) nahezu temperaturunabhängig, während sie bei dickeren Schichten mit abnehmender Temperatur geringer wird, im direkten Gegensatz zu den anderweitig berichteten hohen Werten bei tiefen Temperaturen [12]. Ergänzend wird noch von Abweichungen berichtet, welche bei Verwendung von aufgedampftem Zr auftraten.
Domain Wall Creep Rate in Thin Permalloy Films
Authors: Telesnin R. V. , Ilicheva E. N. , Kanavina N. G. , Shishkov A. G. 
Published: July 2007

AbstractAn analysis of the experimental dependence of the domain wall creep rate, V, on the intensity of magnetic fields in the “easy” (HL) and “hard” (HT) directions gives a characteristic exponential dependence of V on HL with HT = const. The parameters of the exponential V (HL) for films of different thickness are presented, and it is shown that one of the parameters should be the critical start field of the wall, Hw. st., rather than the coercivity, Hc. It is shown how the creep parameters vary when the sinusoidal bipolar alternating field along the “hard” axis is replaced by a unipolar magnetic field.
Theory of the Optical Spectrum of Ion Pairs of 3d3 Iron‐Group Impurities in Crystals
Authors: Nikiforov A. E. , Cherepanov V. I. 
Published: July 2007

AbstractA calculation is made of the energy spectrum of impurity ion pairs with 3d3 configuration in crystals. The optical spectrum of these crystals is interpreted by assuming that a large part of the low‐symmetry crystalline field acts on the impurity ion; the electric‐dipole interaction being taken into account. The case of ruby (Cr3+:Al2O3) is treated in detail as an example. The results are compared with experimental data.
Photo‐Field‐Emission from High‐Resistance Silicon and Germanium
Authors: Borzyak P. G. , Yatsenko A. F. , Miroshnichenko L. S. 
Published: July 2007

AbstractThe characteristics of field and photo‐field‐emission from high‐resistance Si and Ge at low temperature are presented. On the basis of a dielectric field cathode model, the nature of the dark current and the conditions of voltage redistribution across the emitter and vacuum gap are discussed. The photofield emission characteristics are also discussed.
Structured Luminescence Emission in Cadmium Sulphide at 2.0 to 2.8 μm
Authors: Bryant F. J. , Cox A. F. J. 
Published: July 2007

AbstractFor cadmium sulphide a new structured luminescence emission in the wavelength region 2.0 to 2.8 μm and the corresponding excitation spectra are reported. The luminescence is believed to occur at an acceptor centre analogous to that responsible for the 1.5 to 2.2 μm banded emission. Cadmium sulphide phosphors which exhibit luminescence between 2.0 and 2.8 μm also show an apparent shift of the well‐known 1.06 μm emission band to shorter wavelengths, the shift is caused by the existence of a new luminescence emission band with an intensity maximum at 0.90 μm. By considering the new acceptor centre and a common donor level the 0.90 μm luminescence emission band may be explained on the same donor‐acceptor pair model previously proposed to explain the origin of the 1.06 μm luminescence emission band. Comparision of absorption and emission transitions for the two luminescence centres on the model proposed to explain the 1.06 μm and 1.5 to 2.2 μm emission bands leads to a consistent value of approximately 0.2 eV for the energy separation of the two acceptor levels.
Electrical Properties of Single Crystals of Hexagonal Ferrites with the W Structure
Authors: Šimša Z. , Zalesskij A. V. , Závêta K. 
Published: July 2007

AbstractSingle crystals of a hexagonal ferrite of composition BaFe18O27 with the W‐structure are found to have an anisotropic electrical conductivity, which is believed to be an intrinsic property of the material. From the temperature dependence of the electrical resistivity, and from thermoelectric measurements, it is concluded that electron hopping between Fe2+ and Fe3+ ions plays a prominent role in the conduction process. The possible origin of the anisotropy in the conductivity is discussed in relation to specific features of the W‐structure.
Investigation of Current Carrier Drift in Organic Substances (Tetracene)
Authors: Frankevich E. L. , Balabanov E. I. 
Published: July 2007

AbstractThe pulses of hole conduction current induced by pulse electron bombardment in a thin sublimed film of tetracene are studied. It is shown that electrons produced by ionization cannot be extracted into the bulk of the sample by an external electric field. The hole mobility is estimated as μ ≧ 0.5 cm2/Vs. The integral of hole current per pulse is shown to rise with the applied voltage U, though special experiments demonstrate that no trapping occurs in the sample. The linear increase of the hole current integral is explained by competition between extraction of holes from the electrode‐adjacent layer and recombination of holes with electrons injected into the tetracene from the Al electrode. This conclusion is confirmed by the rectifying properties of the Al‐tetracene contact and by photovoltage. The hole current integral in the admixture containing samples is shown to be proportional to U2. This is due to a combination of two processes: the hole extraction probability increases linearly with U and also the hole displacement before trapping in the sample increases linearly with U.
The Effect of Exposure to Air on Dislocations in Zinc and Cadmium Crystals
Authors: Michell D. , Ogilvie G. J. 
Published: July 2007

AbstractX‐ray topographs of initially perfect and unstrained crystals of zinc and cadmium show that loops and line defects nucleate and grow in them as a result of their exposure to air. This phenomenon is attributed to the growth of an oxide film causing vacancies to be injected into the crystal which aggregate to produce the visible defects. Observations on cadmium crystals in an electron microscope show nucleation and growth of similar defects and these results can be explained using the same model.
Bestimmung der Diffusionskoeffizienten des Nickels und der Leerstellenkonzentration in der β‐Phase des Systems Nickel‐Antimon
Authors: Heumann Th. , Stüer H. 
Published: July 2007

AbstractIn der β‐Phase des Systems Nickel—Antimon zeigt das Nickel eine ungewöhnlich hohe Beweglichkeit. Messungen mit dem radioaktiven Nickelisotop Ni63 ergaben Frequenzfaktoren von etwa 5 × 10−4 cm2/s und Aktivierungsenergien von ungefähr 15 kcal/Mol. Durch Bestimmung der makroskopischen Dichte sowie der Gitterkonstanten der β‐Phase in Abhängigkeit von der Konzentration konnte nachgewiesen werden, daß die große Beweglichkeit des Nickels durch strukturelle Leerstellen bewirkt wird, die dadurch auftreten, daß mit wachsender Antimonkonzentration Plätze im Nickelteilgitter unbesetzt bleiben. Dabei ergab sich, daß die der vollbesetzten Struktur entsprechende stöchiometrische Zusammensetzung Ni3Sb außerhalb des Homogenitätsbereiches der β‐Phase liegt.
Negative Knight‐Shift und Suszeptibilität in Übergangsmetall‐Hydriden: Chromhydrid
Authors: Albrecht G. , Schnabel B. 
Published: July 2007

AbstractEs wurden eigene Messungen der Größe, des Vorzeichens und der Temperaturabhängigkeit der H1‐Knight‐Shift und der Suszeptibilität im CrH benutzt, um die Einflüsse und Beiträge des Spin‐Paramagnetismus der s‐ und d‐Bänder sowie des Bahn‐Paramagnetismus zu ermitteln. Die Möglichkeit von “exchange‐enhancement” der d‐Spin‐Suszeptibilität wurde diskutiert. Kovalente Bindungsanteile zwischen Cr und H wurden angenommen und die Spin‐Bahn‐Kopplung benutzt, um das negative Vorzeichen des Bahnbeitrages zur H1‐Knight‐Shift zu erklären.
Nachweis großer Schmelzpunktserniedrigungen bei dünnen Metallschichten
Authors: Gladkich N. T. , Niedermayer R. , Spiegel K. 
Published: July 2007

AbstractDie Struktur dünner Silberschichten wurde während des Wachstums bei erhöhten Temperaturen mit Elektronenbeugung in einem Vakuum von 10−9 Torr untersucht. Bei einer Temperatur über 550 °C wuchsen die Schichten zunächst im flüssigen Zustand und gingen erst bei einer bestimmten temperaturabhängigen Schichtdicke in den festen Zustand über. Unter denselben Bedingungen wurde auch der Schmelzpunkt dünner Schichten von Ag, Cu, Al und Ge bestimmt. Für dünnste Schichten konnte eine minimale Schmelztemperatur gefunden werden, und zwar für Ag 550 °C und für Cu 670 °C.
The Mössbauer Effect for 57Fe Impurity Atoms
Authors: Bara J. , Hrynkiewicz A. Z. 
Published: July 2007

AbstractThe Debye‐Waller factors for the 14.4 keV γ‐rays of 57Fe atoms as a dilute impurity in 16 crystal lattices are measured at room temperature. The force constants for the hostimpurity atoms are found to be almost the same as for the host‐host atoms. A correlation between the isomer shifts and the standard electrode potentials is observed.
The Influence of External Electric Fields on the Absorption of Ag+‐Centres in KCl (II)
Authors: Gebhardt W. , Mohler E. 
Published: July 2007

AbstractA group theoretical analysis of Stark effect measurements in KCl:Ag+ is reported. The irreducible representations of the excited states are determined assuming that the electronic transitions associated with the four measured absorption bands arise from the same ground state singlet, and that the Ag+‐centre has Oh‐symmetry. The results can be understood qualitatively by considering the Ag+Cl6−‐complex in terms of MO theory.
Susceptibility Measurements and the Magnetocrystalline Anisotropy of Polycrystalline Ferromagnetic Films
Authors: Leaver K. D. , Prutton M. , West F. G. 
Published: July 2007

AbstractThis paper reports a comparison of observations of the transverse susceptibility with some ripple theories due to a number of authors. A very wide range of films was investigated. It is demonstrated that these theories are qualitatively successful in relating macroscopic magnetic observables to single crystal magneto‐crystalline and magneto‐elastic effects. However, quantitative comparisons require unreasonably large values of magneto‐crystalline anisotropy K1 to fit the observations in cases where magneto‐elastic effects should be negligible. Better fits to the observations and more reasonable values of K1 are obtained for a ripple field theory of the type described by Feldtkeller, but in which the power of the field dependence of the susceptibility is allowed to vary for different films. Such behaviour is consistent with a two‐component model of the magnetization ripple, the properties of which are briefly outlined.
Effects of Liquid Metalls on the Fracture Strength of Germanium
Authors: Pugh E. N. , Westwood A. R. C. , Hitch T. T. 
Published: July 2007

AbstractA study has been made of the effects of certain liquid metals from Groups II to Von the fracture strength of germanium monocrystals tested in three‐point bending over the temperature range 30 to 680 °C. At low temperatures, when the behavior of the solid is purely brittle, the presence of liquid metals causes marked reductions in fracture stress. These are attributed to the notch effect of etch pits produced by the liquid metals. At higher temperatures, when the significant increase in ductility reduces the effect of such notches, true liquid‐metal embrittlement phenomena are observed. Possible correlations between the degree of liquid‐metal embrittlement and the properties of the individual liquid metals are discussed.
The Interaction of Microwave Phonons with Irradiation Centres in Quartz
Authors: Lewis M. F. , Rosenberg H. M. , Wigmore J. K. 
Published: July 2007

AbstractThe electron spin resonance spectrum of the paramagnetic centres produced by the X‐irradiation of quartz has been investigated at 1.8 °K at 10 GHz from well below to above the microwave saturation region. Hypersonics at 10 GHz were then introduced and this reduced the resonance signal. The effect has been studied as a function of hypersonic power and frequency, microwave monitoring power and magnetic field orientation. The experimental results suggest that the spin‐lattice relaxation time is of the order of 6 s at 1.8 °K and is determined by cross relaxation processes.
Simultaneous Diffusion of Argon and Krypton in Single Crystals of KCl‐RbCl
Authors: Schmeling P. , Schroerschwarz R. 
Published: July 2007

AbstractThe simultaneous diffusion of Ar41 and Kr85m into single crystals containing 30 mole percent of KCl and 70 mole percent of RbCl is studied. The rare‐gases are created by irradiation with fast neutrons. The diffusion kinetics are similar to those of the systems KCl/Ar and RbCl/Kr. The interesting high temperature region is characterized by activation energies of (0.28 ± 0.035) eV and (0.56 ± 0.035) eV for KCl—RbCl/Ar and KCl—RbCl/Kr, respectively. The diffusion coefficients of argon are about one order of magnitude higher than those of krypton. Comparison with experiments performed after irradiation to high neutron doses shows that these values are not affected by radiation damage.
Plasma‐Type Oscillations of Kinked Dislocations
Authors: Alefeld G. 
Published: July 2007

AbstractThe oscillation frequencies of interacting kinks of both signs have been determined taking into account long range interaction between kinks. The frequencies are proportional to the square root of the sum of positive and negative kink densities and are consequently temperature dependent, in contrast to the frequencies of the dislocation string model. The temperature dependence of the relaxation time for the phonon scattering peak is therefore determined not only by the temperature dependence of the damping constant B but also by that of the kink densities.
Injektionsbestimmte Defektelektronenströme in Anthracenkristallen
Authors: Riehl N. , Becker G. , Bässler H. 
Published: July 2007

AbstractIn Anthracenkristallen (Harshaw) wurden Dunkelströme parallel zur ab‐Ebene gemessen. Die Kontaktierung erfolgte mit Leitsilber. Eine spezielle Anordnung gestattete die Variierung der Elektrodentemperatur unabhängig von der Temperatur des Kristallvolumens. Es zeigte sich, daß der stationäre Kristallstrom nur von der Temperatur der Anode abhängt. Die zugehörige Aktivierungsenergie beträgt 0,7 eV. Die Injektion von Defektelektronen muß daher geschwindigkeitsbestimmend für den Leitungsmechanismus sein. Sättigungsverhalten wurde nicht beobachtet, da die Injektionsrate angenähert proportional der Feldstärke anwächst. Der Strom ist unabhängig von der Driftgeschwindigkeit der Ladungsträger, so daß Einfang‐ und Ausheizeffekte, die von der Lage des Fermi‐Niveaus für Löcher abhängen, keine Rolle spielen. Schließlich wird gezeigt, daß wahrscheinlich alle früher gemessenen Dunkelströme in Anthracen injektionsbestimmt waren.
Kristallbaufehler beim epitaxialen Wachstum von Silizium auf Magnesium–Aluminium‐Spinell
Authors: Schlötterer H. , Zaminer Ch. 
Published: July 2007

AbstractBis zu 30 μm dicke Siliziumschichten, die durch thermische Zersetzung von SiCl4 bei ca. 1200 °C in Wasserstoffatmosphäre auf synthetischen Spinelleinkristallen epitaxial abgeschieden worden waren, konnten mit Hilfe der Methode der Ionenätzung bis auf eine Dicke von 0,1 bis 0,5 μm abgetragen werden. Diese gedünnten Schichten ließen sich im Elektronenmikroskop durchstrahlen und untersuchen. Dabei zeigte sich, daß im auf solche Weise hergestellten Silizium verschiedene Arten von Kristallbaufehlern enthalten sind, nämlich viele primäre Wachstumszwillinge und Versetzungen, gelegentlich auch sekundäre Wachstumszwillinge und Tripyramiden. Der kristallographische Nachweis der Zwillingsnatur geschah durch Kombination von Elektronen‐Feinbereichsbeugung und elektronenmikroskopischer Dunkelfeldabbildung. Der Einfluß der Kristallstörungen auf die elektrischen Eigenschaften der Siliziumschichten wird diskutiert.
Antiferromagnetic Structure of Uranium Diphosphide
Authors: Troć R. , Leciejewicz J. , Ciszewski R. 
Published: July 2007

AbstractThe antiferromagnetic structure of tetragonal UP2 below the Néel temperature (203 °K) is determined by neutron diffraction with polycrystalline samples. The magnetic unit cell is twice the size of the chemical one along the c‐axis. The magnetic structure consists of ferromagnetic sheets of uranium stacked along the c‐axis in the order + − − +. The magnetic moments of the uranium are parallel to the c‐axis; their magnitude is (1.0 ± 0.1) BM.
Zur Analyse des Ummagnetisierungsprozesses von Strontiumferritmagneten
Authors: Heinecke U. , Müller H.‐G. 
Published: July 2007

AbstractEin Vergleich der drei von Wohlfarth angegebenen Remanenzarten, gemessen an anisotropen Strontiumferritmagneten mit Magnetisierungskoerzitivfeldstärkewerten von 2800 Oe zeigt, daß die umgerechneten Kurven große Abweichungen voneinander aufweisen. Es wird ein sukzessives Verfahren zur Analyse der inneren Schleifen angegeben, mit dem diese Abweichungen einmal im Prinzip auf die von Kooy und Enz bekannten Magnetisierungsschleifen von Bariumferriteinkristallen und zum anderen auf eine positive Wechselwirkung zwischen den einzelnen Kristalliten zurückgeführt werden können. Bei der Deutung der Ergebnisse werden die reversiblen Magnetisierungsänderungen mit berücksichtigt.
Electromechanical Effect in Semi‐Metals
Authors: Upit G. P. , Varchenya S. A. , Spalvin I. P. 
Published: July 2007

AbstractThe electromechanical effect representing a decrease of microhardness of the surface layer due to an electric field applied between the sample and the indenter is observed in the semimetals antimony and bismuth. The dependence of the magnitude of this effect upon load, electric field intensity and indenter orientation is investigated. The inconsistencies of the concepts regarding the mechanism of the photomechanical and electromechanical effects are discussed. An attempt is made to explain the effects on a common basis. It is suggested that an increase in the mobility of dislocations which appear on the surface is caused by a change of surface energy or bond metallization in a surface layer.