bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and Magnetic Properties of Epitaxial Permalloy Films
Authors: Escudier P. , Biragnet F. , Devenyi J. , Yelon A. 
Published: July 2007

AbstractA study is made of the structural and magnetic properties of (111) films of permalloy (80% Ni, 20% Fe), produced epitaxially (111) Ag on mica. The orientation of the NiFe is parallel to that of the Ag. The anisotropy field is about 2 Oe, and the coercive force is slightly less than this value. The dispersion, α90, is of the order of a degree. The films are largely uniaxial, with a superimposed triaxial component. The presence of a triaxial component is demonstrated by the slow switching properties of the permalloy films, and by their domain structures. It seems that the reversal process, away from the easy axis, is a partial rotation.
Thermally Activated Domain Wall Movement
Authors: Craik D. J. , Wood M. J. 
Published: July 2007

AbstractMagnetization reversal by slow domain wall motion under constant applied field has been observed by the Faraday effect in permalloy films. A quantitative study (Craik and Wood 1965) of the dependence of wall velocity on temperature and field has been made in the temperature range −47 to +22°C. The linear relationship between the field H and the logarithm of velocity is consistent with previous work, but in addition the variation of the slope of this line with temperature is noted. The analysis of the results is based on Stacey's theory for uniform potential barriers, and an activation volume deduced which is approximately equal to the cube of the film thickness. An estimate is also made of the frequency factor incorporated in the theory, which is consistent with theoretical values. The validity of these calculations is discussed.
Influence of the Perpendicular and Parallel Anisotropy on the Ferromagnetic Properties of Thin Films
Authors: Corciovei A. , Costache G. 
Published: July 2007

AbstractA calculation is given of the dependence of the spontaneous magnetization in a thin film on the temperature and the number of monoatomic layers in the film. The dependence of Curie temperature on the number of monoatomic layers is also calculated, taking into account the effects of perpendicular and parallel magnetic anisotropy. This work is an extension of a previous theoretical study by Corciovei.
Some Remarks About Electronic Correlation in Crystal Surfaces: The Ideal (100) Surface of a Semi‐Infinite Diamond‐Like Crystal
Authors: Tomášek M. 
Published: July 2007

AbstractThe simple qualitative method for treating electronic correlation in crystal surfaces, suggested recently by the author and by Davison and Amos, is discussed in detail. As an example, a study is made of the effect of interelectronic repulsion on the behaviour of electrons localized near an ideal (100) surface of a diamond‐like crystal. The spin‐degeneracy of the electron surface states is found to be split and possible physical consequences of this splitting are mentioned. Surface states lying in “forbidden” bands differ from volume states in their sensitivity to the magnitude of the volume state energy bands seem to have the same sensitivity to the interelectronic repulsion as the volume states.
Quantum‐Statistical Calculations on the Work Function of Metals
Authors: Dubejko M. , Olszewski S. 
Published: July 2007

AbstractWork functions of metals with atomic numbers below 40 are calculated using the statistical atomic theory. Good agreement with experiment is obtained for the average value of the work function for each element. For a metallic solid solution with a small heat of mixing the expected work function is rather close to that of the component having the lowest work function and rather insensitive to changes in atomic concentrations.
Zeitabhängigkeit raumladungsbegrenzter Injektionsströme in Fe‐dotiertem p‐Silizium
Authors: Lemke H. 
Published: July 2007

AbstractEs wird über Impulsmessungen raumladungsbegrenzter Ströme bei p+‐p‐p+‐Kristallen mit eindiffundierten Anreicherungskontakten berichtet. Aus der Zeitabhängigkeit des Injektionsstroms kann die Einfangwahrscheinlichkeit rc (H‐H) bestimmt werden. Bei Vorliegen einer gegenüber der thermischen Löcherkonzentration großen haftenden Raumladungskonzentration erfolgt die Haftstellenentleerung bei stark abgesenkter Löcherkonzentration, wodurch der Retrapping‐Einfluß vernachlässigbar ist. Für die zeitliche Änderung der haftenden Raumladungskonzentration ist das Verhältnis von injizierter getrappter Trägerdichte ΔH+(0) zu der im thermischen Gleichgewicht vorhandenen Zentrenbesetzung H maßgebend. Bei hoher zusätzlicher Besetzungskonzentration erfolgt die Entleerung nach einer Exponentialfunktion, wodurch eine direkte Bestimmung der Emissionswahrscheinlichkeit re ermöglicht wird. Bei kleiner injizierter Trägerdichte ist die zeitliche Anderung der haftenden Raumladung konstant und proportional zu re H. Aus den Emissionswahrscheinlichkeiten erhält man für den Wirkungsquerschnitt (Löcher) des Eisenzentrums g · Θp = 0,7 × 10−15 cm2 (g statistischer Gewichtsfaktor).
A Field Ion Microscope Study of Neutron Irradiated Tungsten
Authors: Attardo M. , Galligan J. M. 
Published: July 2007

AbstractA study of the damage introduced into tungsten by fast neutrons using field ion microscopy, is described. This consisted of examining the type of damage as reflected in the vacancy content of the material and the removal of the vacancy content after various annealing treatments. Evidence is presented which shows that vacancies are removed from tungsten in stage IV. The observations also indicate the presence of depleted zones in the irradiated tungsten.
On the Mechanism of Sputtering
Authors: Lehmann Chr. , Sigmund P. 
Published: July 2007

AbstractIt is shown that spot patterns in single crystal sputtering do not necessarily arise as a consequence of focused collision sequences. Spots can be obtained if it is assumed that only the surface of a solid has regular structure. The spot width is determined by the energy distribution in the collision cascade and the potential barrier at the surface. The contribution of focusons to sputtering is negligible at low bombarding energies because of the small penetration depth of the ions. Recent experimental results indicate that the average pa thlength offocusons contributing to sputtering is extremely small even at high bombarding energies, so that the proposed sputtering mechanism should be dominant over the whole energy range. This result appears to be consistent with collision cascade theory if forward scattering is taken into account.
Zur Theorie des Ferromagnetismus magnetisch anisotroper Schichten mit kubischer Kristallstruktur II. Berechnung der Curietemperatur für eine Eisenschicht mit (100)‐Oberflächenorientierung
Authors: Brodkorb W. , Haubenreisser W. 
Published: July 2007

AbstractFür eine Eisen‐(100)‐Schicht werden die ferro‐ und die paramagnetische Curietemperatur als Funktion der Anzahl der Netzebenen berechnet. Es wird ein Vergleich zwischen den Ergebnissen des Molekularfeld‐Modells, der Methode der Greenschen Funktion und experimentellen Daten gegeben.
Determination of the Displacement Vector at the Anti‐Phase Boundaries in Rutile by Contrast Experiments in the Electron Microscope
Authors: van Landuyt J. 
Published: July 2007

AbstractContrast experiments are used to determine by transmission electron microscopy and electron diffraction the displacement vector associated with the anti‐phase boundaries in rutile. The criteria derived elsewhere [3] for the contrast at π‐boundaries are applied, and the conditions for extinction of the contrast are also used to determine the vector. A vector of the type 1/6 〈211〉 is found, which is in disagreement with the 1/2 〈101〉 vector previously proposed [1, 2]. The method used here is general and could be used to find the displacement vector at a stacking fault or an anti‐phase boundary in other materials.
Electrical Properties of Anthracene Single Crystals at Very Low Temperatures
Authors: Thoma P. , Vaubel G. 
Published: July 2007

AbstractThe dark current characteristics of anthracene single crystals are measured for a wide range of field strengths up to breakdown at temperatures of 4, 77, and 293 °K. Above the trap‐filled limit the logarithmic current‐voltage characteristic has slopes of the order of 5 to 7. It is shown that this part of the characteristic can be described by a simple expression. The photovoltages under the action of uv excitation are measured and represented analytically. Using a glow‐curve method it is shown that anthracene crystals have quasicontinuous trap distributions for electrons and holes. Because of their lower concentration the distribution of electron traps is observed as a sequence of discrete trap levels.
Properties of Recrystallized Evaporated CdS Layers
Authors: Böer K. W. , Feitknecht J. W. , Kannenberg D. G. 
Published: July 2007

AbstractRecrystallization of evaporated CdS layers in an environment containing N2, HCl, O2, Cu, and CdS at 630°C are investigated using electron microscopic and electron probe analysis, and show an oxygen enhanced single crystal growth with preferably (001) parallel to the substrate surface. Photoconducting layers of unusual high frequency response for modulated light excitation (35% value at about 100 KHz), low electronic noise (above 60 Hz due to density fluctuation) and high photosensitivity, at 170°K with a maximum gain factor of 108, and a “useful” light/dark current ratio (after 1 s decay) of 107 at 100 ft.‐c are described. These layers have a trap density of ≳ 3 × 1011 eV−1 cm−3 between 0.3 and 0.4 eV and show with 100 ft.‐c bias illumination at room temperature electron lifetime (30 μs) determined relaxation.
Das Ultrarotspektrum von NaNo2 zwischen 30 und 150 μm in der ferro‐ und paraelektrischen Phase
Authors: Vogt H. , Happ H. 
Published: July 2007

AbstractDie folgende Arbeit befaßt sich mit dem Ultrarotspektrum des Ferroelektrikums NaNO2, dessen Phasenübergang bei 163°C ein Order‐Disorder Übergang ist. Wir haben das Reflexionsspektrum im Bereich der äußeren UR‐aktiven Gitterschwingungen (30 bis 150 μm,) gemessen, und zwar für Polarisationsrichtungen des elektrischen Feldes parallel zu den drei kristallographischen Achsen. In der ferroelektrischen Phase treten fünf Reflexionsbanden auf. Eine von diesen entspricht auf Grund der Gittersymmetrie einer reinen Translationsschwingung der Ionen, während die anderen zu Kombinationen von Translationsbewegungen und Torsionen der NO2−‐Ionen gehören. Bei Erhöhung der Kristalltemperatur von 30 bis 200°C beobachteten wir eine starke Reduktion aller Reflexionsbanden.
Études de la durée de vie et du bruit de génération recombinaison controlés par les dislocations dans le germanium
Authors: Gouskov L. , Lecoy G. , Llinares C. , Savelli M. 
Published: July 2007

AbstractUne étude du bruit de génération‐recombinaison et de la durée de vie mesurée par décroissance de la photoconductivité est effectuée sur une série d'échantillons des types p et n de germanium dopé en impuretés peu profondes. Les dislocations créées à la naissance du cristal, sont représentées par un niveau accepteur situé environ à 0,15 eV au dessous du bas de la bande de conduction, jouant le rǒle de centre recombinant. La variance des porteurs et les durées de vie mesurées sont, dans le domaine 250°K à 350°K, dues aux processus du type Shockley‐Read de transitions bande à bande, par l'intermédiaire de ces niveaux de dislocations.
Effect of a DC Field on the Lattice Diffusion of Silver‐110 in Copper and Gold
Authors: Archipova N. K. , Klotsman S. M. , Timofeev A. N. , Trakhtenberg I. Sh. 
Published: July 2007

AbstractA study is made of the effect of a direct current, with a density of about 100 to 150 A/mm2, on the diffusion of silver‐110 in gold (99.99%) and copper (“high purity” grade) at temperatures above 800°C. Diffusion of silver‐110 is measured by the residual activity method. The direction of the electromigration and the magnitude of the activated ion “effective charge” is clear evidence for electron drag. The “effective charge” decreases linearly with temperature increase. The temperature coefficient of the “effective charge” of silver in gold and copper is higher than the temperature coefficient of the matrix conductivity.
Theory of the Photovoltaic Effect in Semiconductors
Authors: Zuev V. A. , Litovchenko V. G. 
Published: July 2007

AbstractThe detailed theory of “surface photovoltage” is developed for the case of small signals in Si and Ge. In addition to the usual factors considered (such as the spreading of space charge during illumination etc.) other important effects such as the trapping of photocarriers on the surface and the photoconductivity in the space charge region are taken into consideration. Δn involves the surface trapping parameters in addition to the electron—hole pair generation rate. A convenient set of approximate equations are chosen, from the usual relations, to describe the dependence of the photo e.m.f. on temperature, surface potential, and the parameters of the local centres. It is shown that under appropriate simplifying assumptions the expressions obtained reduce to those formerly described.
Some Results Concerning the Co++ Site Symmetry in Alkali Halide Crystals
Authors: Musa M. 
Published: July 2007

AbstractSpectral studies are made of the Co++ ion site symmetry in LiCl and KBr host lattices. It is found that in LiCl and KBr the Co++ ion symmetry is octahedral and tetrahedral respectively. This conclusion is supported by a comparison with CoCl2, Cs3CoCl5, and Cs2CoBr4 spectra. More detailed structures are found in the spectrum of a RbClCo(Zn)Cl2 sample as compared with those exhibited by RbClCo++ single crystals grown from melt.
Elektronenmikroskopische Untersuchung der Wachstumsmorphologie von Zink‐ und Kadmiumeinkristallen
Authors: Nanev Chr. 
Published: July 2007

AbstractEs wird über eine nach dem Platin‐Kohle‐Abdruckverfahren durchgeführte elektronenmikroskopische Untersuchung der Oberflächenmorphologie von Zink‐ und Kadmiumeinkristallen berichtet. Die Kristalle werden unter bestimmten Bedingungen aus der Dampfphase gezüchtet. Die Untersuchung zeigt, daß die Oberflächenstruktur der Kristalle von den Wachstumsbedingungen abhängt. Die Temperaturabhängigkeit der Gleichgewichtsform der Kristalle wird geklärt und auf dieser Basis eine gute Übereinstimmung der experimentellen Daten mit früheren Ergebnissen über die Gleichgewichtsformen von Zink [3] gefunden, die durch direkte mikroskopische Beobachtung der Anfangswachstumsformen erhalten wurden.
The Anomalous Vectorial Photoemission from a Cesium‐Antimony Layer
Authors: Hora H. , Kantlehner R. 
Published: July 2007

AbstractThe photoemission from a transparent cesium‐antimony layer is measured. A special arrangement of the cell allows a 75° angle of incidence of the light, so that the reflected and transmitted intensities can be determined simultaneously. With an E‐vector perpendicular or parallel to the plane of incidence, the absolute quantum yields Q are measured as functions of the absorbed light. In this way it is possible, apparently for the first time, to determine the absolute ratios of polarization yield Kabs = Q⊥/Q∥ for large angles of incidence. With glass‐side illumination the vector effect is anomalous (as in previous results), having maximum Kabs values of 1.7 in the region of phonon energies of 2.2 eV. By contrast, the Kabs values are within 10% of unity with vacuum‐side illumination. Besides the virtual absence of the vector effect, there is a small systematic variation around unity. This shows that the electron excitation process is almost isotropic in the direction opposite but parallel to the motion of the photons. Only in the forward direction can anisotropy with a preferred direction perpendicular to the E‐vector be deduced. This is analogous to the Compton effect and may be explained as a predominance of indirect transitions. The ratio of the probability of indirect to direct transitions is estimated, and from this the band structure beyond the minima may be determined.
On the Feasibility of a “Composite” Martensite Model for the (225)f Austenite‐Martensite Transformation
Authors: Morton A. J. , Wayman C. M. 
Published: July 2007

AbstractIn an attempt to account for the (225)f habit in iron alloys a “composite” martensite model has been proposed. Several features of the composite model are examined herein. The assumption that the interface (between the parent and the martensite) is macroscopically undistorted does not appear justified, and the proposed martensite fine structure is not in agreement with that which is observed by transmission electron microscopy.
Hall Effect and Magnetoresistance of n‐InP Crystals at Low Temperatures
Authors: Aliev S. A. , Kesamanly F. P. , Lagunova T. S. , Nasledov D. N. 
Published: July 2007

AbstractA study is made of the temperature dependence of the Hall constant R(T), the electrical conductivity σ(T), and the magnetoresistance Δ∥/∥(T) between 1.7 and 300 °K in specimens with electron concentrations from 2 × 1016 to 1018 cm−3. A maximum is observed in R(T) in the temperature range 20 to 100 °K; Δ∂/∂ is negative in all specimens below the maximum temperature of R(T). The results are explained by the participation of impurity band conduction.
Akustische Aktivität
Authors: Kluge G. 
Published: July 2007

AbstractMit Hilfe der Methode der langen Wellenlängen werden die akustischen Zweige bis zur dritten Näherung untersucht. Breiten sich die Schallwellen in einer Richtung aus, in der sich der Kristall akustisch isotrop verhält, so erhält man für nicht primitive Gitter neben der longitudinalen Welle eine rechts‐ und eine linkszirkular polarisierte Welle, die bei gleicher Frequenz verschiedene Wellenlängen haben. Das heißt, die Polarisationsebene einer transversalen Schallwelle wird gedreht, der Kristall verhält sich akustisch aktiv. Es wird weiter ein Experiment vorgeschlagen, mit dem man die akustische Aktivität nachweisen könnte.
Zero‐Phonon Lines of Color Centers in LiF and NaF
Authors: Kazumata Y. , Kamikawa T. , Ozawa K. 
Published: July 2007

AbstractThe optical absorption of LiF and NaF irradiated by electrons or neutrons is measured at liquid He temperature and above. In these crystals zero‐phonon lines are observed on the F‐aggregate centers. From the temperature dependence of the relative intensities of zero‐phonon lines and broad bands, Debye temperatures are deduced using the Debye approximation, and the semi‐local mode approximation based on the Debye model. Debye temperatures obtained by this method are different in each F‐aggregate center. The coupling between the trapped electrons in the lattice defects and the lattice waves is discussed and interpreted in terms of both the local and normal modes.
Die Temperaturabhängigkeit der Defektelektronenbeweglichkeit in Siliziumkristallen
Authors: Elstner L. 
Published: July 2007

AbstractEs wurde die Temperaturabhängigkeit der Hallbeweglichkeit an hochgereinigten und dotierten p‐leitenden Siliziumeinkristallen im Temperaturbereich von 20 bis 300 °K gemessen. Unterhalb von 100 °K können die Ergebnisse durch eine kombinierte Streuung der Defektelektronen an akustischen Gitterschwingungen und an ionisierten Störstellen erklärt werden. Bei alleiniger Streuung an akustischen Phononen gilt auch im p‐Silizium das T−3/2‐Gesetz. Zwischen 100 und 300 °K wird der Einfluß einer zusätzlichen Streuung an optischen Phononen diskutiert.
On the Magnetization Directions in the Heisenberg Antiferromagnet ‐ The Random‐Phase Green's Function Method
Authors: Przystawa J. 
Published: July 2007

AbstractThe isotropic Heisenberg antiferromagnet with two inter‐penetrating, translationally invariant, ferromagnetic sublattices is investigated by a Green's function technique in RPA. From the requirement that the Green's functions must not contain the poles at E = 0, the equations for the magnetization vector directions are obtained. These equations are the same as derived in a previous paper using other methods.
Raman Spectrum and Phase Transition in the Ferroelectric Crystal NaNO2
Authors: Chisler E. V. , Shur M. S. 
Published: July 2007

AbstractThe temperature dependence of frequencies of bands at 119, 153, and 220 cm−1in the Raman spectrum of the ferroelectric crystal NaNO2is investigated over the temperature range 40 to 220 °C. An abnormal decrease of the frequency of the dipole vibration at 153 cm−1is discussed on the basis of the Ginzburg‐Anderson‐Cochran theory. On the basis of the experimental data it is concluded that the phase transformation is due to reorientation of the NO−2group around an axis perpendicular to the anion plane.
Temperature Dependence of Oblique‐Incidence Anisotropy in Permalloy Films
Authors: Weber P. , Ruske W. 
Published: July 2007

AbstractThe temperature dependence of the oblique‐incidence anisotropy of approximately non‐magnetostrictive permalloy films evaporated onto unheated substrates is investigated. Characteristic experimental results are as follows: 1. For isothermal annealing the time dependence of the constant of uniaxial anisotropy, Ku, is logarithmic. 2. During annealing Ku changes its sign. 3. The reversible changes of Ku as a function of temperature correspond to that of M28 (Ms saturation magnetization). A tentative explanation of the results is given on the basis of known structural properties of oblique‐incidence films.
Magnetic Anisotropy Induced in Thin Films at Low Temperatures
Authors: Andrä W. , Steenbeck K. 
Published: July 2007

AbstractThe directional ordering of hydrogen atoms reported previously by Adler is investigated for single‐crystals films 96% Ni‐4% Co. The orientation dependence predicted by the same author is confirmed. It is found that an additional anisotropy which also exists in pure Ni without hydrogen can be induced below room temperature. This anisotropy may possibly be explained by the action of Ni interstitials in the dumb‐bell configuration or by divacancies. It is also found that anisotropy can be induced by field annealing at T = 80 °K for time intervals of about 1 min.
Über die Pippardsche Theorie des magnetischen Durchbruchs in Metallen
Authors: Fischbeck H. J. 
Published: July 2007

AbstractDie Pippardsche halbphänomenologische Theorie [2] des magnetischen Durchbruchs in Metallen wird durch Transformation und WKB‐Behandlung der Schrödingergleichung quantenmechanisch begründet. Dadurch kann der Pippardsche Durchbruchparameter unmittelbar definiert werden. Aus seiner Magnetfeldabhängigkeit ergibt sich die Blountsche Bedingung (δE)2 ≪ħ ωc ℰF für das Auftreten von magnetischem Durchbruch.
Züchtung von Einkristallschichten aus Eisen, Nickel, Kobalt und deren Legierungen
Authors: Kirenskii L. V. , Pynko V. G. , Sivkov N. I. , Pynko G. P. , Sukhanova R. V. , Ovsyannikov M. A. 
Published: July 2007

AbstractEs wird eine Untersuchung des Wachstums von Epitaxieschichten ferromagnetischer Metalle und ihrer Legierungen auf NaCl‐, KCl‐ und LiF‐Kristallen durchgeführt. Die Kristalle werden dazu im Vakuum gespalten oder bei 10−4 Torr getempert. Im letzteren Falle wird gefunden, daß eine bestimmte Zusammensetzung der Restgase besonders günstig für epitaxiales Wachstum ist.
On the Origin of M‐Induced Anisotropy in Nickel and Permalloy Films
Authors: Kneer G. , Zinn W. 
Published: July 2007

AbstractThe anisotropy field strength HK is measured in thin nickel and 81/19 nickel‐iron films immediately after deposition and during subsequent systematic annealing in external magnetic fields. These measurements are performed with the films kept in ultra high vacuum using a planar Hall effect method. An analysis of the HK‐isotherms and of the temperature dependence of HK gives the spectrum of HK‐contributions of a given film with their relaxation times and activation energies. In non‐magnetostrictive permalloy the main contribution to the anisotropy (of 60 to 85%) is attributed to directional ordering of the iron pairs. In nickel a complicated concurrence of several anisotropy contributions is found. The contribution of the magnetoelastic energy dominates; it can be understood in terms of the constraint model.