bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystallization of a germanium melt in an external electric field
Authors: Kanter Yu. O.
Published: January 2007

Data are presented on experimental studies of the influence of an external electric field on crystallization of a germanium melt under the layer of a B2O3 flux. It has been found out that with the field supercoolings of the melt sharply change. This effect is due to the change of the number of active nucleation centres at the germanium – B2O3 flux interface. The maximum supercoolings of the germanium melt ΔT− = 190 K were obtained when a negative potential was connected to germanium. The dependences of supercooling on preliminary melt overheating were measured.
The texture of GaSb ingots grown by the bridgman method
Authors: Koltai F. , Hársy M. , Lendvay E.
Published: January 2007

Crystallographic features of GaSb grown by the Bridgman procedure were investigated by scanning electron microscopy. Chemical etching and the electron channelling method were used to determine the position and crystallographic orientation of crystallites. A pronounced 〈110〉 texture was detected which was misaligned by 5÷28° with respect to the main axes of the ingots. Boundaries were categorized according to the orientation change accross them. Results were compared. The majority of small angle boundaries are probably caused by thermal stresses induced dislocation migration.
The influence of gas‐phase etch removal, deposition temperature and substrate properties on the crystallographic perfection of silicon epitaxial layers
Authors: Richter F. , Weidner G. , Borchardt A. , Bugiel E. , Kittler M. , Schmalz K. , Weidner M. , Rausch H.
Published: January 2007

An investigation of the defect structure of silicon homoepitaxial layers, as influenced by gas phase etching, deposition temperature, and substrate properties, is presented. The minimum values of etch removal and deposition temperature necessary for sufficient layer perfection have been determined. The defect and impurity distribution in the substrate, as formed during a preceeding arsenic buried layer processing, have been evaluated and are discussed here with regard to their influence on the epitaxial layer perfection.
Growth of calcium phosphate crystals in Silica gel
Authors: Kibalczyc W. , Sokołowski T. , Wiktorowska B.
Published: January 2007

The results of a study of the crystal growth of calcium phosphates in silica gel employing double diffusion system with CaCl2 and KH2PO4 aqueous solutions are reported. Liesegang rings, spherical crystalline agglomerates and brushite dendrites are formed near the CaCl2 solution. It was found that the agglomerates consist of octacalcium phosphate and hydroxyapatite crystals with the predominance the former.
On some experiences with the thr notation for CdI2 polytypes
Authors: Fichtner K.
Published: January 2007

The advantages of the thr notation are discussed using 12 recently reported polytypes as examples. It is shown that the thr notation combines the advantages of the Zhdanov notation with those of the t‐o‐f notation. An almost trivial conversion of Zhdanov sequences into thr sequences and vice versa is given. The restrictions in the stacking of CdI2 polytypes and the relations between homometric structures can be described in the most simple way using the thr notation.
Study of electrical properties in mixed oxide sandwich structures
Authors: Siva Kumar J. , Narayana G. , Chandra Shekar M. , Subba Rao U. V. , Hari Babu V.
Published: January 2007

I—V characteristics of sandwiched Al—(SnO2 + Sb2O3)—Al mixed films have been studied for different thicknesses. The current‐voltage curves in general exhibit three regions, ohmie, non‐ohmic and breakdown regions. The breakdown voltage increases and the dielectric strength decreases with increase of film thickness. The de breakdown studies have been done and optical photomicrographs of breakdown patterns during different stages of de voltage have been taken and the results are discussed.
Magnetic phase transitions in LaMnO3+λ
Authors: Pavlov V. I. , Bogush A. K. , Balyko L. V.
Published: January 2007

Magnetic properties of nonstoichinometric lanthanum manganite LaMnO3+λ as a function of the Mn4+ concentration (from 0 to 27%) and temperature (from 77 to 300 K) are investigated. The Mn4+ ions concentration depends on the degree of oxidation λ. It is shown that at 0–10% Mn4+ there exists an antiferromagnetic ordering and at 10–14% — mixed ferro‐antiferromagnetic ordering, while at Mn4+ concentration exceeding 14% the ferromagnetic ordering takes place. The concentrational antiferromagnetic‐ferromagnetic transition at 14% Mn4+ is due to the crystal structural O' — O orthorhombic transition. In ferromagnetic O‐orthorhombic lanthanum manganite the phase ferromagnetic‐paramagnetic transition occurs via intermediate magnetic state where in the paramagnetic matrix there are noninteracting ferromagnetic impurity clusters. The presence of such magnetic state gives rise to anomalous behaviour of magnetic and galvanomagnetic properties of LaMnO3+λ near Curie temperature.
The coprecipitation of Magnesium Nickel Oxalate Dihydrate Powders (solid solutions) from aqueous solution: Precipitate compositions and Cporecipitate Mechanisms
Authors: Packter A. , Omomo A.
Published: January 2007

The coprecipitation of magnesium nickel oxalate dihydrates from mixed metal cation solutions was monitored by conductivity measurements. A series of coprecipitates was then prepared from 0.2 M solutions with Mg contents varying from 0.2 to 0.9 total metal cation and their compositions and structures studied by chemical analysis, infra‐red spectrophotometry, thermogravimetric analysis and detailed differential calorimetry. The coprecipitates with upto 20 percent Mg content were solid solutions with structures similar to nickel oxalate dihydrate, the coprecipitates with 20 to 80 percent Mg content were probably mixed solid solutions while the coprecipitates with over 80 percent Mg content were solid solutions with structures similar to magnesium oxalate dihydrate.

The ionic equilibria in supersaturated magnesium nickel oxalate solutions were analysed and mechanisms are proposed for coprecipitations from solutions of different Mg/(Mg + Ni) ratios.
Formation of space‐charge electric field and space charge during the cleaving of Alkali Halide Crystals
Authors: Gromov V. V. , Rozno A. G. , Romanov A. V.
Published: January 2007

The “acoustic probe” method has been used for the measurement of the space‐charge and polarization in the crystals LiF, NaF, KCl and NaCl exposed to mechanical action. It has been shown that large mechanical stresses in the bulk of crystals lead to the formation of space‐charges and inhomogeneous polarization. The reason for this phenomenon is, probably, the motion of dislocation pile‐ups.
On facets existed on concave interfaces in Czochralski‐grown GaSb crystals
Authors: Kumagawa Masashi , Hayakawa Yasuhiro
Published: January 2007

It is tried to make facet regions grow on interfaces curved concavely toward the melt using the Czochralski method. By increasing rapidly the pulling rate of crystals, the whole growth interface is once remelted and a concave interface is formed in the following growth process. A facet region occurs from a (¯I¯I¯I) plane which appears by the remelt of interfaces. This facet continues to grow while it is being surrounded by concave interfaces of nonfacet regions. From the microscopic measurement of spreading resistance. the impurity concentration is higher in the facet region than in non‐facet ones. This suggests that the growth mechanism of the facet on concave interfaces is the same as that on convex ones.
Double crystal topographic investigations of PbTe grown by the travelling heater method (THM)
Authors: Winkler M. , Genzel C. , Parthier L. , Gille P.
Published: January 2007

THM‐grown PbTe and PbTe: Tl were examined near the (n, —n)‐position by means of X‐ray double crystal arrangement. The half‐width of the rocking curves of Tl doped PbTe is larger than that of undoped PbTe by factor two. Long range and local lattice plane distortions, as well as disturbances induced during preparation, in the from of dislocation slip lines and greatly disoriented areas were observed.
X‐ray triple‐crystal diffractometer investigation of arsenic implanted silicon after pulsed laser irradiation
Authors: Zaumseil P. , Winter U. , Galler R.
Published: January 2007

X‐ray triple‐crystal diffractometry (TCD) of parallel (+n, ‐n, +n) setting was used to investigate the structural changes of silicon surface layers after arsenic implantation and pulsed laser irradiation. The implated layers of different doses show enlarged lattice constants in the disturbed crystalline parts. After low energy annealing a polycrystalline surface layer is built up from the amorphous layer while the crystalline layer below it is not significantly changed. High energy annealed regions show recrystallisation with high degree of perfection and decreased lattice constant. The results of TCD measurements are compared with results of double‐crystal diffractometer investigations and advantages of the TCD method are discussed.
The structure of Dimethylaminomethanediphosphonic Acid, C3H11NO6P2
Authors: Kulpe S. , Seidel I. , Szulzewsky K.
Published: January 2007

Mr = 218.9, monoclinic, P 21/c, a = 6.870(1), b = 10.824(2), c = 11.337(2) Å, β = = 94.59(2)0, Z = 4, V = 840.5(3) Å3, Dx = 1.73 Mgm−3. Final R = 0.033 for 2648 independent reflections, excluding those with |F0| < 3σ(F0). Intensities were measured with an automatic diffractometer. This organophosphorous compound is characterized by two PC bonds. Four symmetrically independent intermolecular hydrogen bonds determine the threedimensional packing of the molecules and the unique chemical properties of the campound.
Radiation‐controlled enhancement of electroluminescence in Calcium Sulphide Electroluminors
Authors: Bhushan S. , Chandra F. S.
Published: January 2007

Enhancement and quenching effects in electroluminescent emission from CaS:Cu, Er and CaS:Cu, Sm electroluminors under the concurrent action of electric field (a.c. or d.c.) and radiation (3650 Å) has been investigated. Variation of the ration R defined by R = (BE+/BE + BL) has been studied as a function of voltage (a.c. or d.c.) and frequency (a.c.) of the applied field. The net effect is found as combination of enhancement and quenching. Sometimes peaks (one or more than one) are also found. With the increase in frequency of a.c. field higher value of R is found. No regular variation with increase in intensity of uv radiation is found.
Grain boundary migration in high‐temperature deformation
Authors: Gifkins R. C.
Published: January 2007

Observations of grain‐boundary migration in both creep and fatigue are reviewed and grouped into thirteen classifications, particularly noting the relationship between migration and grain‐boundary sliding. It is concluded that all experimental observations so far have been of more than one of these classifications and none give unambiguous support to the hypothesis that sliding and migration are coupled through the motion of grain boundary dislocations. Several sets of results using bicrystals are particularly difficult to reconcile with this hypothesis.
Dislocation mobility in LiF at low temperatures
Authors: Suzuki Takayoshi , Nakamura Kazuo
Published: January 2007

The mobility of dislocations in LiF has been measured at 4.2 and 10 K by means of an etch pit technique. The average velocity of screw dislocations is 2–5 times as large as edge dislocations. The results of the stress and temperature dependence of the velocities correlate well with the data of the critical shear stress in the same temperature region, and are well described by the theory of Peierls mechanism with thd Peierls stress of about 20 MPa for edge dislocations on {110} slip plane.
Study of the instability boundaries of plastic flow in Cu + 14 at.% Al single crystals at low temperatures
Authors: Komnik S. N. , Demirski V. V.
Published: January 2007

The authors experimentally revealed the existence of the temperature‐strain rate region of jumplike deformation in Cu + 14 at.% Al single crystals between 4.2 and 25 K. For each particular temperature in this temperature range, there are a lower and an upper critical strain rates, between which deformation is jumplike. The character of transients occurring during strain rate variation was investigated by increasing the strain rate to the lower critical value. The experimental data are explained in terms of the thermomechanical instability concept and inertial effects of the sample‐machine system.
Fracture‐induced luminescence in Alkali Halides
Authors: Strube W. , Linke E.
Published: January 2007

Crack propagation in dielectric solids is connected with many structural and electronic excitation processes. In order to obtain some information on the elementary excitation mechanism, crack velocity and fracture‐induced luminescence in LiF and NaF (as received; doped; X‐irradiated) under high vacuum conditions were correlated. Time‐resolved crack velocity measurements revealed the usually discontinuous manner of crack propagation; maximum crack velccities of 3800 m/s (LiF) and 3000 m/s (NaF) were observed. Luminescence excitation in the X‐irradiated samples occured at slow crack motion i.e. for increased plastic processes in the crack tip zone. The luminescence was explained by the recombination of stabilized radiation defects (F‐centres and interstitial halogen atoms) involving a radiative exciton decay. The recombination is triggered by the crack via mobilization of the recombination partners by dislocations or lattice deformation processes.
On the nature of instability of the hardening and structural states in crystals with forest dislocations
Authors: Lavrentev F. F.
Published: January 2007

The branch of studies of work‐hardening and the related structural states as yet has not been developed sufficiently. This paper touches upon the problem of work‐hardened state formation by a dislocation forest and its stability against a range of infiuences.
Crystal and molecular structure of (E)‐21‐Methoxycarbonyl‐19‐nor‐pregna‐4,8(14),20‐trien‐3‐one
Authors: Reck G. , Schubert G.
Published: January 2007

The crystal and molecular structure of the title compound has been determined by X‐ray diffraction techniques. It crystallizes in the orthorhombic space group P 212121 with cell parameters a = 12.662 Å, b = 17.995 Å, c = 8.433 Å. The structure was solved by direct methods using MULTAN‐78 and refined by least‐squares calculations to the conventional R = 0.061. The ring conformations of the steroid skeleton and the 17β‐side chain conformation are discussed in detail.
The mechanism of the rotation of single‐crystal spheres during sintering
Authors: Wieters K.‐P. , Boiko I. J. , Schatt W.
Published: January 2007

A dislocation mechanism is presented which explains the fast rotation of particles as observed during the sintering of rows and loose packings of monocrystalline copper spheres. The experimentally determined data agree well with the data determined by calculation. They are important for the production of sintered filters.
Solid‐phase epitaxy for the formation of superlattices based on A3B5 compounds
Authors: Sheftal R. N.
Published: January 2007

To form superlattices based on A3B5 compounds, it is suggested to use solid‐phase epitaxy (SPE) which includes recystallization of super‐thin films of stoichiometric composition deposited by laser evaporation on single‐crystal plates or films with the same or close composition. The recrystallization temperature is shown to be reduced considerably for the film grains with its curvature differing significantly from zero and which are in contact with their own single‐crystal seed having practically zero curvature. The single‐crystal multilayer films GaAs‐(Al, Ga)As … GaAs were formed at 300°C. The recrystallization rate at this temperature was 40 Å/min. The autocatalytic action of the single‐crystal seed strongly reduced the activation energy of the SPE process, which may be due to diffusion in solid phase.
Structure sensitivity of relaxation phenomena in NaCl and KCl crystals doped with some divalent impurities [I] ITC‐spectra characteristic of the as‐cleaved state
Authors: Suszynska M. , Capelletti R.
Published: January 2007

ITC spectra of NaCl and KCl crystals doped with europium, lead, and nickel (in a wide concentration range) have been measured at temperatures between 120 and 400 K. It has been shown that the spectra taken for as cleaved samples are usually very rich. The origin and behaviour of the high‐temperature peaks (above the IV‐dipole peak) have been discussed in frames of the SILLARS theory of Maxwell/Wagner‐type polarization effects in heterogeneous dielectrics. It is suggested that the peak positioned near room temperature is related with any type of vacancy rich precipitates formed within otherwise homogeneous crystal lattice. The second peak, positioned at still higher temperatures, is a Maxwell/Wagner effect due to dislocations surrounded by impurity‐related imperfections in a fashion of the so called Cottrell atmosphere.
Shaped crystal growth of PbTe by the open tube technique
Authors: Klimakow A. M. , Höfer Ch.
Published: January 2007

The possibility of growing shaped AIVBVI crystals from the vapour phase by the open tube technique was investigated on PbTe. The thermodynamic conditions to reproducible prepare several habits of PbTe crystals — whiskers, tetrahedral prisms and cubes, platelets (a), dendrites, cubic and octahedral skeletons (b) as well as their properties were examined. The crystalline habits (a) are characterized by perfectly mirror‐like (100) surfaces and low dislocation densities. The type and concentration of charge carriers are mainly determined by the vapour composition within the crystallization zone and very from n = 3 × 1017 to p = 1 × 1019cm−3. These properties are the reason of the interest in shaped PbTe crystals for the aim of IR optoelectronic devices.
Chemical‐mechanical polishing of n—PbTe and n—Pb1‐xSnxTe crystals
Authors: Hitova L. , Trifonova E. P.
Published: January 2007

PbTe and Pb1‐xSnxTe crystals are of very low hardness. Their mechanical treatment (cutting, lapping, polishing) results in the formation of a thick damaged surface layer (ENGEL et al.). The removing of the damaged layer by etch polishing affects the wafer planarity. The latter is of major importance when the wafers are used as substrates for epitaxial growth. The quality of the treated surfaces is significantly better when chemical‐mechanical polishing (CMP) is applied. For CMP of p‐PbTe and p‐Pb1‐xSnxTe BREITSAMETER et al. have proposed a solution containing potassium hexacyanoferrate (III), sodium hydroxide, glycerol or ethylenglycol. For CMP of Pb1‐xSnxTe STERNBERG and YELLIN have applied a solution of Br2 in HBr. This etchant, however, is strongly corrosive and requires the use of a special equipment.

In the present work the conditions for CMP of n‐PbTe and n‐Pb1‐xSnxTe (x ∼ 0.2) with the etchant proposed by BREITSAMETER et al. have been investigated.
The morphology of witherite and strontianite grown in Silica Gel, by slow precipitation and on hydrothermal conditions
Authors: Franke W. , Hofer A. , Jelinski B. , Lenk K.
Published: January 2007

Both the gel method, slow precipitation, hydrogen carbonate transport at room temperature as well as hydrothermal transport in a carbon dioxide solution and the hydrothermal decomposition of the oxalates were used to grow BaCO3 and SrCO3. The morphology of the resulting crystals is described and compared with respect to theoretical considerations including the Donnay‐Harker rule and the PBC theory.
Basal twinning as a room temperature plastic deformation mode of chromium‐ and titanium‐doped sapphire crystals
Authors: Müller B. , Schulze D.
Published: January 2007

The degree of basal twinning caused by indentation was determined quantitatively on a series of chromium and titanium doped sapphire crystals with variours dopant contents. It depends on the dopant content significantly. The effect of titanium ions in reducing the degree of twinning is more pronounced than that of chromium dopants. This “size effect” of the dopant ions is consistent with the mechanism of basal twinning as reported by KRONBERG.
Neutron texture investigations of hard magnetic MnAl bars
Authors: Fuentes L. , Walther K. , Feldmann K. , Drechsler L. P. , Vlassova E. N. , Matorin V. I. , Betzl M.
Published: January 2007

In the present work connection between magnetic properties and texture of two samples of the tetragonal MnAl phase are investigated. For texture studies classical angle dispersive neutron diffraction and neutron time‐of‐flight method have been applied. the process of specimen preparation is shortly described. The mathematical treatment of experimental data for complete texture analysis has been outlined. The texture of investigated samples is weak. Some main components in inverse pole figures are inclined with respect to the direction of easy magnetization. In this way the non‐optimal magnetic properties of the investigated material can be explained.
Crystal and molecular structure of (21R)‐3β‐acetoxy‐14,21‐epoxy‐5β,14β‐card‐20(22)‐enolide
Authors: Pfeiffer D. , Reck G. , Lindig C. , Leibnitz P.
Published: January 2007

The title compound (21R)‐3β‐acetoxy‐14,21‐epoxy‐5β,14β‐card‐20(22)‐enolide crystallizes in the monoclinic space group P21 with 2 formular units C25H34O5 in the unit cell. The lattice parameters are a = 13.471, b = 7.959, c = 10.514 Å and β = 102.73°. The crystal structure was determined by direct methods and refined by least‐squares procedures to the discrepancy factor R = 0.045. Bond length, bond angles, ring conformations and the configuration at C(21) were determined. Intermolecular interactions are only of van der Waals type.
SIMS‐AES investigations of the oxygen adsorption on the (110) surface of Fe71Ni29
Authors: Uhlmann K. , Bardehle C. , Baunackw S. T. , Storbeck F.
Published: January 2007

Oxygen adsorption was investigated on the (110) surface of Fe71Ni29 at room temperature by means of the methods AES and SIMS. Three stages of interaction of oxygen with the surface could be determined. A dissociative chemisorption occurs in the dose range up to 5 L, surface oxides are nucleated between 5 L and about 40 L, and in the case of longer oxygen exposures a thicker oxide layer grows. At first, iron and nickel contribute to the surface reaction in like manner.
Structural characterization of anthracene‐picric acid eutectic system
Authors: Singh N. P. , Shukla B. M.
Published: January 2007

The eutectic composition has been derived from phasediagram studies and the nature of eutectics has been established by thermal and spectral studies. Diffraction studies reveal the establishment of preferential ordering and the crystalline character of eutectics.
On the thermodynamic theory of dislocation etch‐pit formation
Authors: Koziejowska A. , Sangwal K.
Published: January 2007

A logarithmic function of total dislocation energy, which includes Cabrera's and Schaarwächter's dislocation energy equations, is used to derive thermodynamic conditions for etch‐pit formation at dislocation sites. It is found that Cabrera's mechanism holds when the ratio of dislocation core radius rh to Frank's radius rF approaches zero. When 0 < rh/rF < 1, Cabrera‐type mechanism also holds, but the activation energy barrier is smaller than that in the original Cabrera's model and the undersaturation barrier Δμ* for spontaneous nucleation increases with an increase in rh/rF ratio. When rh/rF =1, the value of Δμ* is four‐times the value predicted by Cabrera's model. For rh/rF > 1, Schaarwächtertype mechanism involving no undersaturation barrier holds. A resume of Cabrera's and Schaarwächter's theories is also given.
Comparative characterization of boron‐implanted silicon after pulse laser annealing along single traces by SEM (SE, EBIC) and TEM studies
Authors: Johansen H. , Bartsch H. , Heydenreich J. , Lämmel B.
Published: January 2007

(111) oriented n‐type silicon wafers which were implanted with 2 × 1015 B+/cm2 at 77 K and at an energy of 60 keV are laser annealed (Nd:YAG pulse laser) in air for mean laser powers between P = 1.8 W and P = 4.0 W. The comparative application of scanning electron microscopy (SE, EBIC) and high voltage transmission electron microscopy (HVTEM, 1000 keV) allows an estimation of the annealing quality in separated lines without overlapping. Values specifically ascertained by SEM in the SE contrast mode for the annealing threshold power Pth, the power range for optimal annealing ΔP0 and for the geometric width of the monocrystalline resolidification perpendicular to the direction of the specimen movement (and related to the spot diameter) at different laser pulse powers P agree completely with the results found in EBIC. At an optimal laser pulse power of P0 = 3.2 W HVTEM enables monocrystalline epitaxially resolidified areas free of defects to be identified in the same geometric width as that ascertained by SE and EBIC.
The transportation of brine inclusions in rock salt in a temperature field of a heat source
Authors: Müller E.
Published: January 2007

There are three kinds of brine inclusions in a natural crystal of halite, as follows: a) inclusion totally filled with brine; b) inclusions partially filled with brine and gas (SORBY inclusions) and c) inclusions totally filled with gas. Type a) and b) migrate in the crystal under the influence of a temperature gradient. Type c) inclusions do not move.

This paper deals with the question whether the migration causes tracks in the crystal or not.

In general, no tracks are caused directly by the motion of inclusions. However, there are some phenomena which can be explained as tracks. The reasons of these phenomena are examined and described.
Crystal and molecular structure of 3‐methoxy‐estra‐1,3,5(10)‐triene‐14β,17β‐diol, C19H26O3
Authors: Reck G. , Kretschmer R.‐G. , Schubert G.
Published: January 2007

The crystal and molecular structure of 3‐methoxy‐estra‐1,3,5(10)‐triene‐14β,17β‐diol has been determined by single crystal X‐ray analysis. It crystallizes in the orthorhombic space group P212121 with cell parameters a = 8.965(2), b = 30.520(7), and c = 6.031(2) A. The structure was solved by the POSIT system and refined by least‐squares calculations to the conventional R factor of 0.075. The steroid rings A, B, and C have planar, 7α, 8β‐half chair, and chair conformations, respectively. The ring D is intermediate between 13α, 14β‐half chair and 13α‐envelope. Rings B and C are trans‐fused, and rings C and D are cis‐fused. There are intra‐ as well as intermolecular hydrogen bonds between both hydroxyl groups of the steroid molecule.
Orientation of structure and crystals of TGS and TGS doped with D, al or L, al
Authors: Březina B. , Havránková M.
Published: January 2007

A description of the various orientations of microstructure and large single crystals of triglycine sulphate (TGS) is reviewed. A difference of the orientation of TGS in polydomain state and in two possible singledomain states is discussed. The conclusions are applied to TGS crystals doped with L, alanine or D, alanine.
L‐alanine distribution in the growth pyramids of TGS crystals and its influence on the growth, switching and domain structure
Authors: Březina B. , Havránková M.
Published: January 2007

The full‐faced crystals of triglycine sulphate (TGS) and deuterated homologs substituted by L‐alanine (LATGS and LADTGS, resp.) were grown from growth solutions with various concentrations of the substituent. The distribution of L, alanine (L, al) in various growth pyramids of crystals was measured by the electrical switching method. The stability of domain structure of doped crystals was studied by the liquid crystal method.
Structure refinement with X‐ray powder diffraction data for synthetic calcium hydroxyapatite by Rietveld method
Authors: Pritzkow W. , Rentsch H.
Published: January 2007

Ca5(PO4)3OH, Mr = 502.3, hexagonal, P 63/m, a = 9.4207(3), c = 6.8780(2) Å, V = 528.67 Å3, Z = 2, Dx = 3.156 Mg · m−3, CuKα, λKα1 = 1.54051, λKα2 = 1.54433 Å, μ = 26.25 mm−1, F(000) = 500, T = 294 K. The powder diffraction pattern was analysed by the Rietveld method. The parameters were refined by the program PFSR (DBW2.9) to final R‐factors Rp = 0.079, Rwp = 0.081 and RB = 0.015.
Fundamental laws of fracture region of solids
Authors: Chandra B. P. , Dubey B. N.
Published: January 2007

The present paper reports that the deformation is statistically symmetric even in the fracture region of solids. The major factor in the fracture region of brittle solids is the creation of new surfaces. On the basis of the creation of new surfaces, four fundamental laws are derived for the fracture region of brittle solids. These laws are: (i) New surfaces are created only after a particular strain of the crystal. (ii) For the smaller values of compressive strain, the area of newly created surfaces is directly proportional to the square of the strain. (iii) The proportionality constant between the area of the newly created surfaces and the square of strain may be termed as fracture constant. Mathematically the fracture constant is the area of newly created surface for unit compressive strain of the crystal. (iv) For larger values of the compressive strain, the logarithm of newly created surfaces is directly proportional to the strain. The experimental verification of the laws of fracture region of solids are discussed. The value of fracture constant of certain solids are estimated and their significance is discussed.
The order‐disorder transformation at supercooled melt/crystal transition region of binary melts (I) the master equation
Authors: Chistyakov Yu. D. , Baikov Yu. A. , Schneider H. G. , Ruth V.
Published: January 2007

Binary melts crystallizing with almost perfectly ordered structures if exposed to conditions close to thermodynamic equilibrium exhibit an increasing tendency to form metastable crystals with increasing disorder when these alloys crystallize on the growth conditions of supercooling. Based on the model of a two‐phase transition zone separating a growing crystal from its non‐solid surrounding a kinetic master equation is formulated describing the kinetics of competitive atomic exchange processes within the transition region. The theory considers the case of simple cubic structure with equal particle numbers of two components that form a NaCl‐type lattice at the state of perfect order. In a subsequent paper solutions of the master equation obtained for steady‐state conditions are discussed.
Determination of the complanar geometric lattice parameters of monocrystals with high precision
Authors: Grosswig S. , Jäckel K.‐H. , Kittner R. , Dietrich B. , Schellenberger U.
Published: January 2007

A measuring method is presented which allows to determine the complanar geometric lattice parameters (the amounts of two unit cell vectors and the angle between the both unit cell vectors) of monocrystals with high precision at one crystal point and in one measurement cycle. The efficiency of the method is demonstrated at measurements of two quartz monocrystals.
Investigations of the Thermoluminescence and EPR of mechanically activated and irradiated quartz
Authors: Boden G. , Sahre P. , Ebert I. , Hennig H.‐P. , Jedamzik J. , Prösch U.
Published: January 2007

Thermoluminescence (TL) measurements are useful for a characterization of the state of order in mechanically activated quartz after X‐ray and γ‐irradiation. As the luminescence at room temperature (RT) the TL also decreases with decreasing crystallinity of the quartz. On the contrary, the concentrations of the EPR centers in quartz (E′, oxygen defect electron (ODE)) created by mechanical activation as well as irradiation increase with decreasing crystallinity. It is shown, that the electronic defects, which cause the TL, are different from the EPR centers.
Electrical conductivity and thermoelectric power of nickel‐zinc ferrites
Authors: Satyanarayana R. , Murthy S. Ramana
Published: January 2007

Electrical conductivity (σ) and thermoelectric power (Q) of polycrystalline nickel‐zinc ferrites of different compositions was investigated as a function of composition and temperature. The electrical conductivity in these ferrites is explained on the basis of the hopping mechanism. Plots of log (σT) versus 103/T are almost linear and show a transition near the curie temperature. The activation energy in the ferrimagnetic region is in general less than that in the paramagnetic region. The carrier concentration and mobility of charge carriers has been discussed as a function of composition and temperature.
The crystal and molecular structure of 1β‐azido‐gibberellin A1 monoetherate
Authors: Kutschabsky L. , Voigt B. , Adam G.
Published: January 2007

The three‐dimensional structure of 1β‐azido‐gibberellin A1 monoetherate has been established by X‐ray analysis. The compound crystallizes from acetone‐diethylether in the monoclinic space group P21 with two gibberellin and two diethylether molecules in the unit cell of dimensions a = 7.799, b = 20.745, c = 8.036 Å, β = 110.23°. The final R‐value is 0.059 for 2855 reflections.
Activation parameters of some differently prepared thermoluminophors
Authors: Balarin M. , Hübner K.
Published: January 2007

For some thermoluminophors (LiF, Li2B4O7, CaF2, and CaSO4) a thermoluminescence peak analysis was made in order to characterize the observed processes by their activation parameters. The resulting values for E0 and K as well as the kinetic order are given. For different sample geometry the glow curve parameters can slightly be altered but the activation parameters remain almost invariant. For LiF the whole TL curve was described by a spectrum of resolved, independent levels and corresponding peaks.
Crystal and molecular structure of L‐N‐acetylhistidinamide
Authors: Pfeiffer D. , Reck G. , Oehlke J.
Published: January 2007

Die Titelverbindung kristallisiert in der monoklinen Raumgruppe P 21 mit 2 Formeleinheiten C8H12N4O2 in der Elementarzelle. Die Gitterkonstanten sind a = 8,529, b = 11,735, c = 4,925 Å und β = 94,61°. Die Kristallstruktur wurde mit direkten Methoden bestimmt und mit der Methode der kleinsten Quadrate bis zu einem R‐Wert von 0,033 verfeinert.
Structure sensitivity of relaxation phenomena in NaCl and KCl crystals doped with some divalent impurities (III). The role of concentration and dispersion state of the dopant ions
Authors: Suszyńska M. , Capelletti R.
Published: January 2007

The influence of both the concentration and dispersion state of the dopant upon the behaviour of the high‐temperature depolarization‐band was thoroughly studied for NaCl und KCl crystals doped with Eu++, Pb++, and Ni++ ions.

It has been evidenced that the behaviour of this band can be better explained in frames of the Maxwell(Wagner)Sillars‐model adapted for the dislocation lines surrounded by the Cottrell‐like atmospheres than by the Müller's‐model related to the excess charge conductivity effects.
Thermotropic liquid crystalline compounds with lateral long‐chain substituents (III). Molar volumina, viscosities, optical refractive indices and order parameters of 1,4‐Bis‐[4‐n‐octyloxybenzoyloxy]‐2‐n‐alkylbenzenes
Authors: Demus D. , Hauser A. , Isenberg A. , Pohl M. , Selbmann Ch. , Weissflog W. , Wieczorek S.
Published: January 2007

In the substance class of the general formula magnified image densities, thermal expansion coefficients, viscosities, optical refractive indices and the order parameters of a dissolved dye were measured in the isotropic and nematic states. The results are discussed briefly.
The relative intensity of Mζ‐lines
Authors: Wendt M. , Christ B.
Published: January 2007

Electron excited M‐emission spectra of some heavy elements (64 ≦ Z ≦ 92) were studied by means of energy dispersive X‐ray spectrometry. Large discrepancies to literature data where found for the relative intensity of the Mζ‐line which is usually the strongest of the weak M‐lines. For elements Z ≧ 71 the relative intensity is almost constant and amounts to about 5%. In case of the rare earth elements Gd and Dy higher values of about 20% were obtained which are caused by anomalous self‐absorption effects for Mα and Mβ. These are reflected, too, by unusual high relative intensities of the lines Mγ and M2  N4. The energy of the lutetium Mγ‐line was determined to be (1230.4 ± 0.3) eV.
The influence of the growth temperature on residual impurities in SSD‐GaP
Authors: Kirsten P. , Koil H. , Siegel W.
Published: January 2007

The increase of the growth temperature during the SSD process causes a rise of the growth rate of the GaP. Hall effect and photoluminescence measurements as well as chemical analysis were used to investigate the change of the contents of residual impurities in the GaP in dependence on the growth temperature.

Carbon was detected to be the dominating shallow acceptor in the undoped p‐type SSD‐GaP. Its concentration increases clearly with raising growth temperature whereas for S and N indirectly can be concluded that their concentrations diminish. Carbon and silicon are incorporated in the GaP in part in electrically inactive form.

In all samples exists beside the shallow acceptor a medium deep acceptor the concentration of which is strongly correlated to that of the carbon acceptor. The luminescencespectra of the p‐type samples show a typical broad band with a maximum at 1.90 eV whose origin is discussed.
Decomposition equilibrium of arsine and low pressure doping of epitaxial CVD silicon
Authors: Kokovin† G. A. , Testova N. A. , Titov A. A. , Morgenstern Th. , Kühne H.
Published: January 2007

Calculating the composition of the decomposition equilibrium of AsH3H2 mixtures within the temperature range of epitaxial CVD‐silicon deposition shows AsH2 to be the main component for atmospheric pressure. A drop in total pressure causes As to appear as the second main component. Taking into account AsH2‐ and As particles gives rise to an incorporation of arsenic, less and less depending on total pressure with decreasing pressure. With the aid of the incorporation equation, developed in the present paper, the experimental results on the incorporation of arsenic under reduced pressure obtained by Herring, can be explained clear of contradiction.
Polytypes of the system Fe1−xS
Authors: Kuban R.‐J.
Published: January 2007

The structures of Fe1−xS (0 < x < 0.135) are members of a family of derivative structures in the sense of Megaw. The NiAs structure as aristotype is the simplest and most symmetrical member of this family. The other polytypes of Fe1−xS may be derived as hettotypes by lowering the symmetry. The loss of symmetry in changing from the aristotype to the hettotype may be of various kinds: small displacements of Fe and S atoms from the NiAs positions and/or Fe vacancies in some atomic planes occur. The structures of the system Fe1−xS are interpreted as OD structures consisting of OD layers. The symmetry relations of the structures of FeS and Fe7S8 are described by OD groupoid families. Polymorphism, twinning and stacking faults are explained on this basis.
The defects and spectral properties of sapphire grown by melting methods
Authors: Kulagin N. A. , Litvinov L. A.
Published: January 2007

The paper is devoted to the study of the spectral properties of the sapphire single crystals grown by Verneuil, Czochralski, Cyropulos, Stepanov and horizontal directed crystallization methods. Varing the methods, parameters of growth and starting material purity, one can control the concentration of electronic and hole centers in wide range and spectral properties of sapphire up to the irradiation.
Structure and Composition of Polished PbS Surfaces
Authors: Tomm Y. , Engel A. , Gaskov A. M.
Published: January 2007

{100} surfaces, produced from sublimation grown PbS single crystals by cutting, mechanical and chemical polishing, were characterized with regard to topography, structure and chemical composition. For this purpose, some methods independent from another were used, for instance profile measuring, dislocation etching, X‐ray rocking‐curves, RHEED, Rutherford backscattering (RBS), and AES.

The results allow to describe the change of structural perfection with the depth (damage depth), the concentration profile of the main components (half‐quantitatively), and the significant decreasing of contamination. Following from this study, the model of the damage layer near the surface discussed earlier for PbTe is modified slightly.
Characterization of the Intensity Distribution in a Single Laser Spot Applied to the Annealing of Ion‐Implanted Silicon
Authors: Johansen H. , Bartsch H. , Exner H. , Zscherpe G.
Published: January 2007

By means of the annealing events of ion‐implanted p‐type silicon in liquid phase epitaxy (implantation dose 2.5 × 1016 As+/cm2) the degree of homogeneity of a bent quartz rod diffuser for single pulses of a Q‐switched Nd‐glass laser (λ = 1.06 μm) is investigated using SEM‐EBIC, TEM and RBS. Starting from discrete distributions of EBIC signal heights in the annealing spot the specific distribution of recrystallized monocrystalline and polycrystalline regions as well as the transition between them are proved by TEM diffraction contrast studies. The perfect recrystallization for a locally optimum laser energy density as well as the rectangular shape of the carrier concentration profile are proved by RBS measurements. At different positions of the measuring point within the annealing area RBS, too, renders it possible to point out local inhomogeneities of the energy density distribution in the case of low‐quality beam diffusers.
Dislocation Structure of Epitaxial Ferrite‐Spinel Films
Authors: Aleksandrov L. N. , Mitlina L. A. , Vasilyev A. L. , Mikhailov V. A.
Published: January 2007

The dislocation structure of ferrite‐spinel films obtained on the (001) plane of magnesium oxide has been studied. For the films of Mn and MgMn ferrites there has been found the formation of a cellular dislocation structure, complex dislocation clusters, for the Li ferrite the twinning.

Experimental data are compared with the predictions of the theory of relaxation of internal stresses in heteroepitaxial structures. It has been shown that in the Li → Mn → MgMn ferrite the energy at the interface of magnesium ferrite and oxide ranges from 64 to 9 mJ · m−2, the absolute magnitude of lattice mismatch at a synthesis temperature being 10.328 to 3.451 × 10−3 and the critical thickness of a continuous film 0.02–0.1 μm. The formation of three‐dimensional islets‐nuclei hinders the obtaining of pseudomorphous continuous films. The critical radius (Rcr) of a pseudomorphous islet in the same series of ferrites is 0.2–1.1 μm. For Li ferrite Rexp > Rer, for MgMn Rexp < Rer, that determines the prevailing types of defects. The process of relaxation of thermal stresses is associated with the overcoming of interaction barriers by dislocations and largely dependent on the film composition and temperature.
Preferred Growth of Antimony Single Crystals
Authors: Thakar B. B. , Shah B. S.
Published: January 2007

Single Crystals of antimony were grown by the Chalmer's method from the melt. The crystals were grown under different temperature gradients of 92 °C/cm, 75 °C/cm and 52 °C per cm. The growth velocities were varied from 1.5 cm/hr to 9 cm/hr. At low growth velocities antimony exhibits a preferred orientation in the range 1 cm/hr to 6 cm/hr. No effect of temperature gradient is observed. The results are compared with those of bismuth, cadmium and zinc which are contradictory to what has been observed.
The Molecular and Crystal Structure of 3β‐O‐(2′,3′ ‐O‐isoropylidene‐α‐L‐rhamnopyranosyl) — digitoxigenin
Authors: Pfeiffer D. , Reck G. , Weiland J.
Published: January 2007

3β‐O‐(2′,3′ ‐O‐isoropylidene‐α‐L‐rhamnopyranosyl) — digitoxigenin crystallizes in the monoclinic space group P 21 with two molecules C32H48O8 per unit cell and the lattice constants a = 7.865, b = 6.470, c = 29.803 Å, β = 93.95°.

The structure was solved by direct methods of phases determination and subsequently refined by least squares technique to the final R‐value 0.06. The position of the lactone ring is disordered in the crystal.
A Comparative Study of Existing Polytype Notations with Reference to the CdI2 Polytypes
Authors: Wahab M. A. , Kant Rajni
Published: January 2007

Existing polytype notations have been critically examined to select a single notation which can describe the CdI2 structures completely and most conveniently. A comparative study shows that the Zhdanov notation fulfils both the conditions. However, the ambiguities in the similar looking symbols is removed by employing some simple criteria proposed by Jain and Trigunayat for deciding the equivalent structures. Further, being numerical in nature this is the easiest notation to handle.
Dielectric Behaviour of the Nematic Phase of 4‐n‐Pentyloxyphenyl 4‐(3‐Bromo‐4‐n‐nonyloxybenzoyloxy)‐3‐ethyl‐benzoate (PBNEB)
Authors: Kresse H. , Worm K. , Schäfer W. , Stettin H. , Demus D. , Otowski W.
Published: January 2007

Due to the high viscosity of 4‐n‐pentyloxyphenyl 4‐(3‐bromo‐4‐n‐nonyloxybenzoyloxy)‐3‐ethyl‐benzoate (PBNEB) the dielectric reorientation processes take place in the kHz and MHz range respectively. We observed two different relaxation ranges in the nematic phase from 10 Hz to 10 MHz if the measuring field is parallel to the director and one relaxation range for the perpendicular orientation. Dielectric measurements at 6.7 GHz demonstrate that at this frequency ϵ′∥ and ϵ′⊥ can be regarded as high‐frequency limit. The experimental values are discussed from the point of view of the Meier‐Maier theory.
Dendritic Growth of Ammonium Tartrate Single Crystals in Silica Gel
Authors: Saraf A. G. , Saraf K. B. , Wani P. A. , Bhoraskar S. V.
Published: January 2007

Dendritic growth of Ammonium tartrate single crystals in silica gel at 30 °C is reported. Main stem parallel to the ‘C’ axis is observed. Dendritic growth in initial and final stages with its surface structures are illustrated and described. Growth features are correlated to the growing conditions and reacting components.
Concentration Magnetic Phase Transitions in the (La1−xCaxMnO3 System
Authors: Pavlov V. I. , Bychkov G. L. , Bogush A. K.
Published: January 2007

Comprehensive investigations into crystal structures, electrical and magnetic properties of the (La1−xCax)MnO3 (x = 0 ÷ 0.6) solid solutions are performed. Two concentration magnetic phase transitions are found: antiferromagnetic‐ferromagnetic with x = 0.14 and ferromagnetic (Tc = 150 K) ‐ ferromagnetic (Tc = 260 K) at f = 0.2. It is shown that the first of them is due to the crystal structure O′O orthorhombic transition, the second ‐ to the increase of ferromagnetic interaction at the expense of additional interaction through conduction electrons. A diagram of the magnetic states for (La1−xCax)MnO3 at x = 0 / 0.6 is given.
1H‐NMR and IR Investigations of Phase Situation in Solid Sodium‐Tetramethylammonium Decamolybdate 3.5‐Hydrate at Low Temperatures
Authors: Hodorowicz S. A. , Hodorowicz E. K. , Lasocha W. , Sagnowski S.
Published: January 2007

Sodium‐tetramethylammonium decamolybdate 3.5‐hydrate was investigated in the range of 77 to 293 K by X‐ray diffractometric and wide‐line proton magnetic resonance and IR techniques. At low temperatures the compound undergoes transitions connected with change of reorientations of CH3, H2O and (CH3)4N+ groups.
Preparation and Electrical Resistivity of Intercalation Compounds of Graphitized Cokes with Antimony Halides
Authors: Preiss H. , Mayerhofer K.
Published: January 2007

Preparation of intercalation compounds of a graphitized electrode coke and a synthetic graphite with SbCl5, SbCl4F, SbCl2F3 and SbF6 have been described and stages have been characterized by X‐ray diffraction technique. On applying pressure a de‐intercalation of antimon pentahalides have been found. The stability of intercalation compounds of graphitized cokes to pressure, temperature, organic solvents and aqueous HCI is lower than that of natural graphite compounds. Electrical resistivity of compacted intercalation compounds of different stages parallel and perpendicular to pressure direction decreases with increasing pressure, intercalant concentration and particle size. Intercalation increases anisotropy of electrical conductivity in graphitized coke and decreases it in synthetic graphite.