bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peculiarities of X‐ray diffraction in quartz monocrystals
Authors: Bezirganyan P. H. , Zargaryan Y. G. , Aslanian V. G. 
Published: January 2007

AbstractThe scattering of X‐rays in quartz monocrystals has been investigated. It has been shown, that, even in thick quartz monocrystals, kinematic scattering takes place and pendular bands appear. It has been demonstrated experimentally that only a diffraction pattern of clearance is obtained in bicrystal quartz interferometers, whereas in tricrystal interferometers moiré patterns are not produced. The beam reflected from one part of the crystal is no longer reflected from the other parts of the same crystal.
Dislocations in CdTe
Authors: Nagabhooshanam M. , Hari Babu V. 
Published: January 2007

AbstractTwo different etchants were developed to get boat‐ and triangular type etch pits on CdTe crystals. The subboundaries are shown to be symmetrical tilt boundaries. Dislocation density and microhardness measurements were made on three CdTe crystals grown by Bridgman, Travelling heater and vapour phase technique and were correlated.
Plasticity of high purity iron single crystals (II) surface observations
Authors: Novák V. , Šesták B. , Zárubová N. 
Published: January 2007

AbstractSlip traces were studied on high purity iron single crystals after deformation in tension in the temperature range from 4.2 to 473 K (the same crystals were used for the work‐hardening study described in Part I of this paper). By evaluation of Nomarski interference contrast and by method of repolishing of the surface before incremental loading detailed quantitative information was obtained about slip line pattern in various work‐hardening stages. An improved model of slip processes in stage III of the work‐hardening curve is presented.
Electrons, dislocations, and low‐temperature plastic deformation
Authors: Galligan J. M. 
Published: January 2007

AbstractThe influence of electron drag processes on the plasticity of normal state metals is demonstrated in the case of zinc crystals. These results show that dislocations move as underdamped oscillators at low temperature and that dislocations flutters as they move. This flutter motion, in contrast to kink motion which is expected to have no long range stress, is the dominant drag process at temperatures below ≈ 4.2 K.
Sub‐boundaries on (002) cleavages of Li2CO3 single crystals
Authors: Raju K. S. , Palaniswamy M. , Ramasamy P. , Laddha G. S. 
Published: January 2007

AbstractLinear arrays of dislocations (straight, terminating and curved) are observed on etching with 2% citric acid (002) cleavages of lithium carbonate (Li2CO3) single crystals, grown by zone melting technique. As the dislocations are non‐uniformly spaced and disappear on successive etching, they may not be revealing low‐angle grain boundary, nor slip traces as they are terminating and curved meaning crystallographically non‐oriented. On the observation of experiments on successive etching and etching of matched pairs, it is concluded that the arrays of etch pits reveal dislocation walls (dislocation density 1.1 × 106 — 1.5 × 107 pits cm−2) probably created due to the localized thermal stresses released as a result of high temperature annealing of the crystal during growth. The implications are discussed.
Metallographic and electron microscopical analysis of microdefects in Fz‐silicon crystals
Authors: Hoffmann K. , Pasemann M. , Sevcik S. 
Published: January 2007

AbstractIn dislocation‐free floating‐zone silicon crystals two types of microdefects were observed and analyzed by means of optical and electron‐microscopical methods. Microdefects of type I occur in swirl‐type arrangements throughout the whole wafer and appear as etch hillocks below which one can find second phase particles. Due to the chemical‐mechanical polishing near the wafer surface microdefects of type II are generated which also occur in spiral arrangements. These defects could be identified to be plate‐like vacancy agglomerates on {111} planes.
Chemical and microscopical investigations on Ti‐ and Mg‐doped LiNbO3 single crystals
Authors: Malicskó L. , Cravero I. , Krajewski Th. 
Published: January 2007

AbstractIn lithium niobate single crystals grown by the Czochralski‐technique from Mg‐ and Ti‐doped melts the concentration distributions of the dopants and the microinhomogeneities were investigated using chemical analysis, optical microscopy and scanning electron microscopy in connection with (energy dispersive) X‐ray microanalysis. It was found that Mg dopants, if present in the melt simultaneously with Ti, increase the effective distribution coefficient of the titanium dopants. This results in a higher quality of the crystals because of a probably improved stability of the crystallization front.
A curved‐crystal spectrometer for soft X‐ray emission studies of metals and metallic alloys
Authors: Zschech E. , Wehner B. , Kleinstück K. , Blau W. , Dick M. , Förster E. 
Published: January 2007

AbstractQuantitative comparisons between obtained X‐ray emission spectra of 3d‐transition metal elements and their alloys as well as band structure calculations demand an energetic resolution of the order of E ≈ 1 eV. A highly resolving focussing X‐ray spectrometer is described which allows very high quality X‐ray emission spectra to be obtained. The spectrometer utilizes a spherically bent Si(111)‐crystal operated on the Rowland circle. The selection, fabrication and testing of the crystal are described. A comparison between own measurements of line‐width of Co‐Kα1,2‐ and Cu‐Kα1,2‐emission lines as well as literature values is given. The required energetic resolution can be obtained in the upper range of the Bragg angle δ with the described X‐ray spectrometer and a spherically bent crystal.
Variation of low temperature internal friction at microplastic deformation of high purity molybdenum single crystals
Authors: Pal‐Val P. P. , Kaufmann H.‐J. 
Published: January 2007

AbstractAmplitude and temperature spectra of ultrasound absorption in weakly deformed high purity molybdenum single crystals of different orientations were measured. The results were discussed in terms of parameter changes related to quasiparticle‐ or dislocation oscillations, respectively, dislocation‐point defect interactions as well as defect generation at microplastic deformation.
Correlation of the basic parameters of unidirectional solidification of the Pb‐Sn eutectic
Authors: Wolsczyński W. , Ciach R. 
Published: January 2007

AbstractGeneral conditions of the unidirectional solidification are used to control the process of Pb‐Sn eutectic solidification as well as to predict the desirable values of λ deciding about the physical properties of a final product.
Influence of gel inclusions on the mechanical behaviour of Gypsum
Authors: Raju K. S. , Godehardt R. , Hopfe J. , Pippel E. 
Published: January 2007

AbstractIn a single test tube system, gypsum crystals grown in alcoholic gel comprise of interpenetration twinned crystals at the interface towards the gel, whereas untwinned tabular crystals are observed at greater depths inside the gel. By indentation of the crystals with a microhardness tool and recording the indentation impressions by means of a scanning electron microscope (SEM) and a transmission electron microscope (TEM) it is found that the hardness of the tabular crystals is of the same order of magnitude as those of natural crystals of gypsum, whereas interpenetration twinned crystals show a remarkable increase in hardness. On studying the morphology of cleavage faces and on carrying out energy dispersive X‐ray analysis (EDXA), it is concluded that the increase in hardness of interpenetration twinned crystals with respect to tabular and natural crystals may be due to the role of the inclusion of gel particles during the growth. The implications are discussed.
Activity coefficient and incorporation of Phosphorus into epitaxial CVD Silicon
Authors: Kühne H. 
Published: January 2007

AbstractThe present paper is concerned with the dopant incorporation behaviour at high doping concentrations, at which the conditions for diluted solutions are commonly considered no longer fulfilled. The first part contains a brief discussion of the theoretical aspects of ideal, ideally diluted and real solutions, and Raoult's law as well as Henry's law are reduced to the general solution equilibrium, applied to dopant incorporation. The second part considers the dopant ionization equilibrium according to the conception of REISS, additionally taking into account the high deposition temperatures. It had been concluded that at high doping concentrations both the ionization equilibrium and the solution equilibrium of dopants behave analogous to real solutions, and both equilibria need a correction by special activity coefficients.
Dielectric and electrical studies on Samarium Oxide thin film capacitors
Authors: Chandra Shekab M. , Siva Kumar J. , Subba Rao U. V. , Hari Babu V. 
Published: January 2007

AbstractSm2O3 films were prepared by thermal evaporation using tantalum boats. Current‐voltage characteristics were drawn for different film thicknesses. The breakdown voltage and dielectric strengths were calcualted for different film thicknesses and the applicability of Forlani‐Minnaja relation was discussed. The effect of dc voltage on capacitance and tan δ was studied. The results were explained on the basis of Schottky barriers existing at metalinsulator interface which are due to the presence of oxygen vacancies. The presence of oxygen vacancies were established from thermoluminescence studies. The effect of ac voltage on capacitance and tan δ were also studied and the results were discussed.
Dielectric and electrical studies on as‐grown CeO2 films
Authors: Chandra Shekar M. , Hari Babu V. 
Published: January 2007

AbstractThin film capacitors of CeO2 were fabricated by thermal evaporation. The dielectric properties of these films were studied in the frequency range 0.05–16 KHz at various temperatures, starting from liquid nitrogen temperature to 390 K. The effect of annealing on capacitance and tan δ were studied for different frequencies. The behaviour was explained on the basis of relief in strain energy. The plot between current density and temperature was drawn, and from the slope of the plot the activation energy was calculated and found to be 0.52 ev. The results were discussed.
Hydrated metal halide structures and the HSAB concept
Authors: Balarew Ch R. , Duhlev R. , Spassov D. 
Published: January 2007

AbstractA review of ligand coordinatio in the structures of hydrates of the bivalent Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn and Cd halide salts is made. Differences in the type of environment around the Me2+ are satisfactorily explained using the HSAB (Hard and Soft Acids and Bases) concept: in all structures the tendency for a preferable combination hard cation — hard ligand and soft cation — soft ligand is proved. The paper demonstrates the possibilities of the HSAB concept to solve crystallochemical problems of the type of ligand coordination in the structures.
Influence of low‐temperature thermocycling on anisotropy of the structural state of commercial purity Beryllium
Authors: Verkin B. I. , Lavrentev F. F. , Braude I. S. , Salita O. P. 
Published: January 2007

AbstractThe influence of low‐temperature cycling (300 ← 77 K) on the anisotropy of commerical purity beryllium structural state, obtained by uniaxial hot extrusion has been studied by means of X‐ray method. In initial samples the anisotropy of structural state is shown by the preferential orientation of grains relative to extraction axis.Two types of experiments were carried outTwo types of samples were investigated the samples cut out along and across the extrusion axis. It was shown that cycling in the samples oriented across the extrusion axis led to essential change in initial structural state due to intense twinning. Considerable changes in structures of the samples oriented along the extrusion axis were not observed. The effects are intensified by load application.Thermocycling leads to considerable decrease in grain size (form about 50 μm in initial state to about 30 μm after cycling) and decrease in structural state anisotropy.Nature of the phenomena found is discussed.
Structure sensitivity of relaxation phenomena in NaCl and KCl crystals doped with some divalent impurities (II) effect of plastic deformation
Authors: Suszyńaska M. , Capelletti R. 
Published: January 2007

AbstractBy studying: 1/the role of dislocations in the origin of the C‐ITC‐peak in undeformed crystals, 2/ the effect of plastic deformation upon the behaviour of this peak, and 3/ the recovery of the deformation‐induced changes of the basic characteristics of this peak (HC, TMC) it has been confirmed that dislocation lines surrounded by the Cottrell‐like atmospheres can be considered as polarizable entities related with the high‐temperature dielectrical response of as cleaved NaCl and KCl crystals doped with divalent impurities. The Maxwell/Wagner model of polarization effects in heterogeneous dielectrics satisfactory accounts for the majority of the experimental data. The quantitative analysis of the results obtained yields some additional informations concerning the interaction‐ and motion‐parameters of the defects considered.
Influence of solidification of binary eutectic lamellar systems on surface tension driven convection in zero gravity conditions
Authors: Demo P. , Farkas L. , Kratochvil J. 
Published: January 2007

AbstractThe effect of solidification of the lamellar binary eutectic system on the onset of surface tension driven convection (so‐called Marangoni instability) is studied in a zero gravity environment. Some main general conclusions concerning the possibility for onset of the Marangoni convection within the melt can be drawn from the analysis, viz., the curvature of the free surface has a destabilizing effect on the onset of the flow; the increased perturbed heat transfer rate from the system stabilizes the melt; the onset of the solutal Marangoni convection closely depends on the ratio of the lamellae half‐widths and the solutal Marangoni instability is more sensitive against the perturbations than the temperature Marangoni one.
Role of Z1 centres in radiation hardening of NaCl:Ba2+ crystals
Authors: Narasimha Reddy K. , Lakshmipathi Rao M. 
Published: January 2007

AbstractRadiation hardening studies of undoped NaCl and NaCl crystals doped with barium have been carried out both in the as‐grown state and after quenching them from 650°C. It is observed that the radiation hardening is more in doped crystals and the results are explained taking into consideration the role of Z1‐centres.
DC breakdown studies on CeO2 films
Authors: Chandra Shekar M. , Hari Babu V. 
Published: January 2007

AbstractThe electrical breakdown studies were made on Al—CeO2—Al thin film capacitors using dc voltage. The optical photomicrographs of the breakdown patterns were obtained at several stages of breakdown using universal optical microscope. Breakdown patterns seems to be originated at some inhomogeneity which may cause to form single‐hole breakdown and is followed by propagating mechanism. The results were discussed.
Thermoluminescence and optical absorption studies of NaCl: Gd2+ crystals
Authors: Narasimha Reddy K. , Subba Rao U. V. , Lakshmipathi Rao M. 
Published: January 2007

AbstractThermal annealing of X‐irradiated point defects in gadolinium doped NaCl crystal is investigated by Thermoluminescence (TL) and optical absorption methods. The results of the influence of pre‐heat treatment and optical bleaching on glow curves and the production of Z1‐centres are discussed.
Effect of AC and DC voltage on dielectric properties of CeO2 films
Authors: Chandra Shekar M. , Hari Babu V. 
Published: January 2007

AbstractThe capacitance‐voltage characteristics have been studied for both AC and DC fields of Al/Cerium Oxide/Al thin film capacitor structures. Compared to DC fields, these structures can withstand higher AC fields. Capacitance increases with increase in AC and DC fields. The former behaviour is explained on the basis of presence of oxygen vacancies and the latter one is attributed for the Joule heating phenomena. The presence of oxygen vacancies were confirmed from the thermoluminescence studies on these films.
A simple method to determine the real composition of LiNbO3 crystals
Authors: Földvári I. , Polgár K. , Voszka R. , Balasanyan R. N. 
Published: January 2007

AbstractThe shift of the UV‐absorption edge was applied to determine the real LiNbO3 crystal composition. The accuracy of the method is about 10−2 mole% using a simple commercial UV‐spectrophotometer. The effect of various impurities and other error sources are discussed.
Changes of the growth morphology in insb crystals pulled under the presence of ultrasonic vibrations
Authors: Hayakawa Y. , Kumagawa M. 
Published: January 2007

AbstractIn the Czochralski method, the effect of ultrasonic vibrations on the growth of InSb single crystals was investigated by observing the growth morphology. Remarkable changes which ultrasonic vibrations brought about were: (1) the crystal diameter, (2) the width of the facet region and (3) the inclined angle of non‐facet interfaces near the facet region for the (111) plane. After introducing vibrations, the crystal diameter decreased smoothly with growth time. However, both the facet width and the inclined angle reached each minimum value after 5 to 7 min regardless of the magnitude of vibrational output powers from 30 to 90 W, and they were in roughly proportional relation with each other. The change rates of crystal diameter and of facet width increased with vibrational powers. The decrease of crystal diameter was known to result from the rise of the melt temperature, which was brought by both the mixture of the melt and the thermal energy transformation due to ultrasonic vibrations. The change of facet width depended upon the melt flow itself in addition to the temperature rise.
The energy distribution in the two‐mode X‐radiation field inside perfect crystals
Authors: Bezirganyan A. P. , Bezirganyan S. E. 
Published: January 2007

AbstractThe intensity distribution of a two‐mode X‐radiation field on simultaneous interference of all four waves inside the perfect crystal in dependence on the absorption and availability of the symmetry center in crystal, as well as one the state of polarization and the angle of incidence of the primary beam is studied.
Calculation of the shear stresses in (111)‐ and (001) semiconductor substrates with film edges
Authors: Fischer A. 
Published: January 2007

AbstractAssuming a film‐edge induced stress distribution in an isotropic crystal, the shear stresses in the glide systems of a diamond‐type semiconductor substrate are calculated. Quantitative information on magnitude and position of the respective shear stress maxima is obtained in dependence on crystal orientation and technologically relevant film configurations.
Automated growing of large single crystals controlled by melt level sensor
Authors: Eidelman L. G. , Goriletsky V. I. , Nemenov V. A. , Protsenko V. G. , Radkevich A. V. 
Published: January 2007

AbstractThe process of single crystal pulling is considered with simultaneous starting material make‐up into the melt and heater temperature control in response to a signal generated by the electronic contact melt level sensor, viz.: (i) conditions ensuring the radial broadening steadiness; (ii) effect of melt level displacement, melt temperature changes, changes of solid/liquid interface shape, melt evaporation on the growing crystal diameter; (iii) conditions of crystal purification from impurities and uniform distribution of dopant.
Diffuse X‐ray scattering study of the temperature variation of elastic constants in indium arsenide
Authors: Orlova N. S. 
Published: January 2007

AbstractThe elastic constants of indium arsenide have been determined in the temperature range from 80 to 750 K on n‐type samples with a carrier concentration of about 8 · 1017 cm−3 by Wooster's method from the measurements of the thermal X‐ray diffuse scattering intensities. An average decrease in the elastic constants with increasing temperature over the above mentioned temperature range is found to be about 8%.
A complex method for structural investigation of GaAs1−xPx epitaxial layers grown on GaAs substrates
Authors: Petrov Sr. , Popov A. , Atanasova R. , Ivanov Iv. 
Published: January 2007

AbstractA universal X‐ray diffractometer is used for the structural complex investigation of GaAs1−xPx epitaxial layers, grown on the (100) face of GaAs substrate. Information is obtained from the analyses of diffraction patterns for some qualities of the epitaxial layers: crystallographical orientation, composition, thickness, as well as structure of the transition region. The suggested complex method has important advantages against the standard Laue method. It is far easier express and convenient for serial investigations.
The reversion of smoky quartz coloration in crystals with induced growth striations
Authors: Bernhardt H.‐J. 
Published: January 2007

AbstractInduced growth striations in quartz crystals grown from Al‐containing material have been investigated after X‐raying them. Earlier results (Bernhardt, Alter) showed that the stripes may occur as strong colored ones on a light background or as light stripes on high coloration background. This behaviour depends on the growth region regarded, and the applied X‐ray dose. The position of the stripes may become displaced in dependence of the X‐ray dose. The present paper developes a model which may describe this effect only using the diffusion law, the smoky quartz centre model according O'Brien and the Al3+/Na+‐distribution in the crystal. Our results must be taken into account when interpreting the growth striations.
On the influence of various pre‐ageing treatments on the structure changes taking place at elevated temperatures in alloys of the type AlZn5Mg1
Authors: Korngiebel E. 
Published: January 2007

AbstractInvestigated were two alloys of Type Al‐5 wt% Zn‐1 wt% Mg, one of them contained additionally 0.2 wt% of Mn, Cr, Fe as well as Si (technical alloy), be means of hardness and TEM investigations.
Effect of high oxygen doping on the minority carrier lifetime in heat‐treated silicon crystals
Authors: Glinchuk K. D. , Litovchenko N. M. , Salnic Z. A. , Skryl S. I. 
Published: January 2007

AbstractEffect of high oxygen doping on thermally induced changes in the minority carrier lifetime τ in 800 °C heat‐treated silicon crystals is studied and analyzed. Deteriorated τ values in prolongly annealed highly oxygen‐enriched Si crystals compared with those found in annealed oxygen‐poor crystals, are observed. This is explained by an appearance in prolongly annealed highly oxygen‐enriched silicon crystals of oxygen‐induced microdefects which are effective in the minority carrier recombination.
Melting temperature and debye temperature of ternary chalcopyrite semiconductors
Authors: Samanta L. K. , Ghosh D. K. , Bhar G. C. 
Published: January 2007

AbstractBand state concept has been used for the first time to explain the Melting temperature and Debye temperature of ternary chalcopyrite semiconductors. The experimental results agree quite well with those evaluated from this model. Finally we derive a correlation between the two termperatures.