Showing papers in "Crystal Research and Technology in 1990"

Electrical conductivity and thermoelectric power of lithium‐cadmium ferrites

Abstract: The electrical conductivity (σ) and thermoelectric power (Q) of polycrystalline lithiumcadmium ferrites having the chemical formula Li0.5–x/2CdxFe2.5–x/2O4 where (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) have been investigated as a function of temperature. Lithium-cadmium ferrite with x = 0.4 is found to possess minimum electrical conductivity and lowest Seebeck coefficient. Plots of log (σT) versus 103T are almost linear and have shown a transition near the Curie temperature except in the case of cadmium ferrite. The Seebeck coefficient is negative for all the compositions showing that these ferrites behave as n-type semiconductors. The values of charge carrier concentration and mobility have also been computed. The properties of cadmium-substituted lithium ferrites have been correlated with those of zinc-substituted lithium ferrites, cadmium and zinc being two non-magnetic divalent ions occupying essentially tetrahedral A sites when substituted in ferrites.

Crystal growth and physical properties of monoclinic L‐arginine hydrochloride monohydrate, C6H14O2N4HCl · H2O, and L‐arginine hydrobromide monohydrate, C6H14O2N4HBr · H2O

Abstract: Single crystals of optical quality of L-arginine HCl · H2O and L-arginine HBr · H2O with dimensions up to 80 × 60 × 30 mm have been grown from aqueous solutions by controlled evaporation at about 310 K The isotypic crystals exhibit a quite similar behaviour with respect to morphological, pyroelectric, dielectric, optical, thermal expansion, electrostrictive, electrooptic, elastic, thermoelastic and non-linear optical properties A distinct anisotropy of the longitudinal elastic stiffness is observed with a maximum along the direction of the alignment of the arginine ions Nearly in the same direction a minimum of thermal expansion, dielectric constant and index of refraction is found The pyroelectric, electrostrictive, electrooptic and non-linear-optical effects are of only mediocre magnitude except the electrostrictive constant d211 which surmounts the longitudinal electrostrictive constant d111 of alpha-quartz by a factor three

Infrared lattice vibrations of In2O3

Abstract: Infrared reflectivity spectra of In2O3 samples pressed from powdered material are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. A Kramers-Kronig analysis of the spectra reveals eleven vibrational modes. The results obtained are compared with group theoretical predictions and with existing experimental data. Infrarot-Reflexionsspektren von aus pulverformigem Material hergestellten In2O3-Proben wurden bei Raumtemperatur im Wellenzahlbereich von 180 bis 4000 cm−1 gemessen. Eine Kramers-Kronig-Analyse der Spektren ergibt elf Schwingungsmoden. Die erhaltenen Ergebnisse werden mit gruppentheoretischen Voraussagen und mit existierenden experimentellen Daten verglichen.

Electrical Conductivity and Thermoelectric Power of LithiumZinc Ferrites

Abstract: Electrical conductivity (σ) and thermoelectric (Q) of polycrystalline lithium-zinc ferrites of different compositions was investigated as a function of composition and temperature. 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.

Crystal structure analysis and refinement of Kalabsha kaolinite (Al2Si2O5(OH)4)

Abstract: The crystal structure of the kaolinite mineral from Kalabsha, Aswan, Egypt, has been investigated with a two-step procedure of the X-ray powder pattern-fitting. The unit cell is found to be triclinic, P1, a = 5.1577(15), b = 8.9417(23), c = 7.3967(40) A, α = 91.672(5)°, β = 104.860(2) and γ = 89.898(2)°. The refinements of the non-hydrogen atomic positions showed a reliability factors RWB = 0.037 and RB = 0.0417. The average rotation angle in the tetrahedral layer in 10°.

The d-d transition spectrum and Cu(II)-N bonds of [Cu(2,2′-bipyridine)2 (saccharin)] (saccharin) · 3 H2O

Abstract: Following a recent upsurge of interest in saccharin complexes system, we have synthesized several saccharin mixed ligand complexes and attempt to discussed them. In this work, the d-d transition spectrum of the title compound crystal have been determined and it is explained with scaling radial theory of non-free ions which was proposed by our laboratory. However, the absorption position of d-d transitions of the title compound are at 10474, 12435, 13814, 15627 cm−1. With data in the work of Brown and Shannon, Cu(II)-N bonds of the title compound are discussed and it shows that the coordination ability of saccharin in to copper(II) ion is weaker than that of 2,2′-bipyridine, but more stronger than that of a water molecule.

“Crystallization E.M.F.” Investigation in the lithium niobate pulling process from the melt

Abstract: E.M.F. in the lithium niobate crystal-melt system as a function of pulling and rotation rates, crystal diameter and orientation was determined. Total E.M.F. is a sum of thermo-E.M.F. and “crystallization E.M.F.” Δφ. The logarithmic approximation Δφ = Δφ0 In (1 + /v0), where v is a growth rate, Δφ0 = 3.9 mV, v0 = 1.9 mm/h is adequate. The Δφ magnitude is independent within the experimental error on the rotation rate and crystal orientation, whereas it is slightly increasing along with the diameter increase. Some existing models of electric phenomena accompanying crystal growth are discussed and a new model based on charge carrier injection into solid during growth is proposed.

Thermochemical analysis of native point defects and substitutional carbon and boron in GaAs crystal growth

Abstract: The phase extent of GaAs has been analyzed and compared with published phase diagrams as related to total and partial point defect equilibria including charged and uncharged Frenkel, Schottky, antisite defects and substitutional carbon and boron on both sublattices. The well-known transition between semiconducting and semi-insulating behaviour at 300 K as a function of melt stoichiometry in LEC crystals can be reproduced in our model in which complete equilibrium exists above, only electronic equilibrium below a freeze-in temperature of 1100 K. The corresponding model standard enthalpy of formation of neutral Schottky defects is 4.0 eV, of a pair of neutral uncorrelated antisite defects 3.8 eV, of neutral Ga Frenkel defects 4.1 eV and of neutral As Frenkel defects 3.6 eV. Defect reactions in cooling processes after crystal growth are discussed and shown to be quite different for crystals with high or low dislocation density. Semi-insulating behaviour requires the existence of carbon acceptors if dislocations provide internal sources and sinks for point defects. For ideal crystals carbon would not be necessary. The possible site distribution of C and B is analyzed in its dependence on temperature and chemical potential of As. Constitutional supercooling is negligible in LEC growth. Macrosegregation is severe if the As fraction in the melt deviates more than ±0.02 from the stoichiometric value 0.5. Der Stochiometriebereich von GaAs wurde analysiert und verglichen mit publizierten Phasendiagrammen in Bezug auf totale und partielle Defektgleichgewichte, wobei geladene und ungeladene Frenkel-, Schottky- und Antistrukturdefekte und Substitutionseinlagerung von Kohlenstoff und Bor auf beiden Untergittern berucksichtigt wurden. Der wohlbekannte Halbleiter-Halbisolator Ubergang bei Wechsel der Schmelzenstochiometrie bei LEC Kristallen kann in unserem Modell reproduziert werden, wobei totales Gleichgewicht oberhalb, rein elektronisches Gleichgewicht unterhalb einer Einfriertemperatur von 1100 K angenommen wurde. Der entsprechende Standardwert der Bildungsenthalpie betragt fur neutrale Schottkydefekte 4,0 eV, fur ein Paar neutraler, unkorrelierter Antistrukturdefekte 3,8 eV, fur neutrale Ga Frenkeldefekte 4,1 eV und fur neutrale As Frenkeldefekte 3,6 eV. Beim Abkuhlen des Kristalls nach der Zuchtung hangen die Defektreaktionen von der Versetzungsdichte ab. Falls Versetzungen Quellen und Senken fur die Gleichgewichtseinstellung der Punktdefekte bereitstellen, erhalt man semi-isolierendes Verhalten erst bei Anwesenheit von Kohlenstoff als Akzeptor. Bei Idealkristallen ware Kohlenstoff nicht notwendig. Es wird gezeigt, wie sich C und B in Abhangigkeit von Temperatur und chemischem Potential von As auf die Untergitter aufteilen. Konstitutionelle Unterkuhlung ist vernachlassigbar beim LEC-Verfahren. Starke Makrosegregation ist zu erwarten, wenn der As Bruchteil in der Schmelze mehr als ±0,02 vom stochiometrischen Wert 0,5 abweicht.

Microhardness of Hg1−xCdxTe and Hg1−xZnxTe

Abstract: The microhardness of Hg1−xCdxTe and Hg1−xZnxTe has been measured on monocrystalline samples of Bridgman and THM crystals as a function of composition x by means of Vickers indentation measurements at room temperature. The curves show maxima of about 830 MPa at x ≈ 0.75 for Hg1−xCdxTe and of about 1700 MPa in the range 0.65 ≦ x ≦ 0.8 for Hg1−xZnxTe. The hardness-relaxation behaviour has been measured on {111} samples in order to obtain the internal stress level and to investigate the stress-relaxation behaviour. The theoretical hardening rate dH/d(x)0.5 was compared with experimental values. Die Mikroharte nach Vickers wurde an einkristallinen Bridgman- und THM-Proben als Funktion der Zusammensetzung x bei Raumtemperatur an Hg1−xCdxTe und Hg1−xZnxTe untersucht. Die Kurven besitzen Maxima von etwa 830 MPa bei x ≈ 0.75 fur Hg1−xCdxTe und von etwa 1700 MPa im Bereich 0.65 ≦ x ≦ 0.8 fur Hg1−xZnxTe. Das Harte-Relaxationsverhalten wurde an {111}-orientierten Proben gemessen, um das Niveau der inneren Spannungen zu bestimmen und das Spannungs-Relaxationsverhalten zu untersuchen. Der theoretische Hartungseffekt dH/d(x)0.5 wurde mit experimentellen Werten verglichen.

Phase formation at constantly increasing supersaturation : electrolytic nucleation at galvanostatic conditions

Abstract: A simple theoretical approach treating the kinetics of phase formation at constantly increasing supersaturation is developed. The process of electrolytic nucleation in galvanostatic regime i.e. at time changing cathodic overpotential is analyzed in terms of this formalism. It is found that the atomistic model of nucleation has to be applied in order to describe quantitatively the process of electrolytic phase formation. Es wird ein einfacher theoretischer Formalismus entwickelt, welcher es gestattet, Phasenbildungs-prozesse bei stetig anwachsender Ubersattigung zu beschreiben. Elektrolytische Keimbildung unter galvanostatischen Bedingungen — im Regime steigender kathodischer Uberspannung — wird im Rahmen dieses Formalismus betrachtet. Es wird gezeigt, das zur quantitativen Beschreibung der elektrolytischen Keimbildung das atomistische Modell angewendet werden mus.

New X‐ray rietveld refinement of kaolinite from Keokuk, Iowa

Abstract: The positions of 13 non-hydrogen atoms in the structure of kaolinite from Keokuk, Iowa, were refined in the space group C1 using the constrained X-ray Rietveld refinement. The precision and accuracy of the atomic positions are better than those previously reported. The most frequent e.s.d.'s of the positional parameters range from 0.003 to 0.005; the SiO bond distances are from the interval 1.56(4)–1.68(3) A, and the AlO from 1.80 (5) to 2.07 (5) A. The ditrigonalization angle α characteristic for tetrahedral sheet was found to be 9°, this value is in good agreement with the 11° reported from single crystal data. The correction for preferred orientation was in the form of exp (G cos (2α)), the final factors of agreement were Rwp = 23.1%, RF = 9.2% and S = 1.4.

KTiOPO4(KTP) crystal growth from high‐temperature solutions containing WO3

Abstract: The process of seed growth of KTiOPO4 crystals from three different high-temperature solutions containing WO3, with definite compositions is reported The low viscosity and relatively slight change of the solubility of the KTP with the variation of the temperature allow the growth of adequately large crystals, free from inclusions, in the case of two tested techniques – slow cooling and temperature gradient Conditions to avoid defects in the seed region have been found The relatively high growth rates allow the production of crystals in a 5-day growth run, that can be cut into samples oriented along synchronism for the second harmonic generation(SHG) with dimensions 8 × 8 × 7 mm3 SHG measurements reveal that the quality of the samples considered is comparable with KTP crystals grown from high-temperature nonstoichiometric solutions

Resistance and inductance studies of Bi2−xPbxCa2Sr2Cu3Oy superconducting compounds

Abstract: Bi2−xPbxCa2Sr2Cu3Oy compounds with (x = 0, 0.1, 0.2, 0.25, 0.3 and 0.4) were prepared by solid state reaction. The resistance and inductance results showed that transition temperature increases with increase in lead concentration. The highest value of Tc(0) observed is 109 K for Bi1.70Pb0.30Ca2Sr2 · Cu3Oy. The change of inductance per unit volume at liquid nitrogen temperature as a function of composition showed maximum change in x = 0.30 Pb-doped sample. The results showed that the inductance change is maximum in samples which also showed highest Tc.

Effect of pH on the electrical conductance of saturated aqueous solutions of KH2PO4 and its solubility

Abstract: The specific conductivity of saturated aqueous solutions of KH2PO4 and its solubility are investigated in the pH range between 2.5 and 6.3. It is found that the values of specific conductivity and solubility show minima at pH of about 3.5 and 4, respectively. These observations are discussed in terms of the presence of a variety of species of different concentrations in saturated solutions of different pH. The conductivity data reveal that the solutions are highly associated. The presence of species other than H2PO4− and K+ explains the experimentally observed deterioration in the quality of KDP crystals from solutions of pH deviating from the natural value.

Analytical theory for flexo‐electric domains in nematic layers

Abstract: An analytical theory for flexo-electric domains in planar nematic films with positive dielectric anisotropy is proposed. It can be decided by a simple criterion, whether flexoelectric domains or the ordinary Fredericksz transition will occur. Es wird eine analytische Theorie fur flexoelektrische Domanen in planar orientierten nematischen Filmen mit positiver dielektrischer Anisotropie vorgeschlagen. Mit Hilfe eines einfachen Kriteriums kann entschieden werden, ob flexoelektrische Domanen auftreten oder ob eine Freedericksz-Umlagerung stattfindet.

Investigation of amorphous to crystalline transitions in InSe thin films

Abstract: The amorphous to crystalline transitions in InSe films have been investigated by different techniques. InSe compound was prepared from non-stoichiometric amounts of indium and selenium in vacuum. The electrical conductivity and thermoelectric power measurements were made in films of different thicknesses and annealed for different times. TEP studies revealed that the films are p-type. The conductivity studies have shown transition from amorphous to crystalline. The transition temperature is found to decrease with increase in (i) the thickness of the film, (ii) the time of annealing. Electronmicrographs and selected area diffraction patterns on as-grown and annealed films have been taken and correlated with the conductivity results. The mechanism involved in the amorphous to crystalline transitions has been discussed.

High-frequency dielectric constant of AIIB2IIIC4VI ordered-vacancy compounds

Abstract: The mean high-frequency dielectric constant of ZnIn2Se4, CdIn2Se4, ZnIn2Te4 and CdIn2 Te4 was determined from unpolarized infrared reflectivity spectra measured in the wavenumber range v = 600 – 4000 cm−1. A simple relation based on the quantum dielectric theory for multibond crystals is proposed to estimate the mean high-frequency dielectric constant of the AIIB2IIIC4VI compounds from individual bond susceptibilities. The results of the calculations are compared with existing experimental data, and susceptibilities of the HgCVI bonds are estimated. Die mittlere Hochfrequenzdielektrizitatskonstante von ZnIn2Se4, CdIn2Se4, ZnIn2Te4 und CdIn2Te4 wurde aus im Wellenzahlbereich v = 600 – 4000 cm−1 mit unpolarisierter Strahlung aufgenommenen Infrarotreflexionsspektren bestimmt. Es wird eine einfache, auf der quantendielektrischen Theorie fur Kristalle mit Mehrfachbindungen basierende Beziehung fur die Abschatzung der mittleren Hochfrequenzdielektrizitatskonstanten der AIIB2IIIC4VI-Verbindungen aus den Suszeptibilitaten der Einzelbindungen vorgeschlagen. Die Ergebnisse der Rechnungen werden mit vorhandenen experimentellen Daten verglichen, und es werden, die Suszeptibilitaten der HgCVI-Bindungen abgeschatzt.

Crystal and molecular structure of 6,13‐Di(ethoxycarbonyl)‐7,12‐dimethyl‐dibenzo [b.i.]‐1,4,8,11‐tetraaza[14]annulenato(2‐) nitrosocobaltat [C26H26O5N5Co] and the neutral ligand [C26H28O4N4]

Abstract: Both title compounds crystallize in the orthorhombic space group Pnma with 4 formular units in the unit cell The lattice parameters are: [C26H26O5N5Co], a = 8589(4), b = 19395(3), and c = 14850(3) A;[C26H28O4N4], a = 8413(7), b = 19166(4), and c = 14807(28) A The crystal structures have been determined by direct methods and refined by full-matrix least square calculations The ligands have a pronounced saddle-shaped conformation in each structure because of interactions of the methyl groups with the benzene rings The overall conformations of the neutral ligand and the cobalt complex are remarkably similar Die Titelverbindungen kristallisieren in der orthorhombischen Raumgruppe Pnma mit 4 Formeleinheiten in der Elementarzelle Die Gitterkonstanten betragen: [C26H26O5N5Co], a = 8,589(4), b = 19,395(3) und c = 14,850(3) A; [C26H28O4N4], a = 8,413(7), b = 19,166(4) und c = 14,807(28) A Die Kristallstrukturen wurden mittels direkter Methoden gelost und mit der Methode der kleinsten Fehlerquadrate verfeinert Die Liganden weisen eine „saddle-shaped” Konformation auf, welche durch die Wechselwirkung der Methylgruppen mit den Benzenringen entsteht Die Konformation des freien Liganden und des Cobaltkomplexes sind annahernd gleich

Preparation and fundamental physical properties of Sn2SbS2I3 and Pb2SbS2I3 compounds

Abstract: The oriented ingots of isostructural compounds Sn2SbS2I3 and Pb2SbS2I3 were prepared using a modified Bridgman method. The lattice parameters of the prepared orthorhombic compounds have been determined by a X-ray powder diffraction analysis. From the spectral response of the photoconductivity the following values for the forbidden zone of the prepared sulfides-iodides were found: Eg(Sn2SbS2I3) 1.5 eV, Eg(Pb2SbS2I3) = 2.0 eV.

Crystal structure and magnetic properties of some Mn2Sb-based alloys

Abstract: The results of the investigation of structural and magnetic properties of the Mn2(Ni)Sb, Mn2(Cr,Cu)Sb Mn2(Ti,Zn)Sb alloys are reported. The solubility limits of the elements substituting Mn in the Mn2Sb matrix, keeping the crystal structure of the Cu2Sb(C38)-type, are established and the lattice parameters temperatures of magnetic phase transitions, specific magnetization of the materials are determined. The influence of thermal treatment and thermal cycling on the magnetic properties of the alloys, which is interpreted by the quantitative redistribution, depending on temperature, of the amount of the main δ-phase (C38) in the samples, with the phase composition changing, and that of an additional nickel-arsenide ϵ-phase has been found. [Russian Text Ignored].

Study of sintering processes in copper and nickel by positron annihilation

Abstract: In the advanced stage of non-isothermal sintering, vacancy clusters are present as prevailing type of defects. Their concentration considerably decreases at further temperature increase, and it can be concluded that thermally activated conversion of multiple vacancies into climbable dislocations takes place. Hence, in conformity with recent experiments, coincidence of intensive material transport ( e-maximum) and decrease of defect concentration (recovery) can be understood.

IR- and 27Al-NMR-spectroscopic studies on thermal decomposition products of basic aluminium chlorides

Abstract: The formation of corundum by thermal decomposition of basic aluminium chlorides was studies by means of spectroscopic methods (IR, 27Al-NMR) It was tried to get information about the short-range order, because favourable structural conditions in the amorphous precursors for the formation of corundum were supposed For this purpose IR-spectroscopy turns out to be the less informative method 27Al-NMR-spectra show resonances of tetrahedrally, octahedrally and fivefold coordinated Al in the decomposition products The corundum proceeds from sixfold and fivefold coordinated Al Die Korundbildung durch thermische Zersetzung von basischen Alummiumchloriden wurde mittels spektroskopischer Methoden (IR, 27Al-NMR) untersucht Ziel waren Informationen uber die Nahordnungsverhaltnisse, da fur die Korundbildung gunstige strukturelle Bedingungen in den amorphen Vorlauferphasen vermutet wurden Fur diesen Zweck erwies sich die IR-Spektroskopie als die weniger aussagekraftige Methode Die 27Al-MAS-NMR-Spektren zeigten Resonanzen von tetraedrisch, oktaedrisch und funffach koordiniertem Al in den Zersetzungsprodukten Der Korund geht aus sechsfach und funffach koordiniertem Al hervor

Crystal structure investigation of [Mn(3‐CH3C5H4N)2(N3)2(H2O)2]

Abstract: The crystal structure of the title compound has been determined by single crystal X-ray diffraction methods. [Mn(3-CH3C5H4N)2(N3)2(H2O)2] crystallizes in the space group P 1 with a = 7.444(2) A, b = 7.691(2) A, c = 8.926(3) A, α = 99.82(3)°, β = 108.80(2)°, γ = 114.99(2)° and Z = 1. Least squares refinement gave a R value of Rw = 0.046 for 1414 observed reflections. The manganese atom in the title complex is octahedrally coordinated by two oxygen atoms of the water molecules and four nitrogen atoms; two N-atoms are the end atoms of azide groups and the other two nitrogen atoms belong to the 3-methylpyridine molecules. The polyhedra are linked via hydrogen bonds between the water molecules and the azide groups. Die Kristallstruktur der Titelverbindung wurde mittels Rontgeneinkristallmethoden bestimmt. [Mn(3-CH3C5H4N)2(N3)2(H2O)2] kristallisiert in der Raumgruppe P 1 mit a = 7.444(2) A, b = 7,691(2) A, c = 8.926(3) A, α = 99,82(2) A, β = 108,80(2) A, γ = 114,99(2)° und Z = 1. Die Verfeinerung nach der Methode der kleinsten Fehlerquadrate ergab einen Rw-Wert von 0,046 fur 1414 beobachtete Reflexe. Das Manganatom des Titelkomplexes wird oktaedrisch von zwei Sauerstoffatomen der Wassermolekule und von vier Stickstoffatomen umgeben. Zwei N-Atome sind Endatome von Azidgruppen, die weiteren Stickstoffatome stammen von den beiden 3-Methylpyridin-Molekulen. Die Koordinationspolyeder sind uber Wasserstoffbrucken zwischen den Azidgruppen und den Wassermolekulen verknupft.

Dependence of Electrical Conductivity (σ) and Activation Energy of Lithium Ferrite on Sintering Temperature and Porosity

Abstract: The electrical conductivity (σ) of lithium ferrite sintered at 950, 1000, 1050 and 1100 °C was investigated in the temperature range of 300 to 1000 K. Three distinct regions have been observed in log (σT) vs 103/T curves for four samples of lithium ferrite sintered at different temperatures. The conduction in the first region is due to impurities. In the second and third region is due to ordered and disordered state of the material. The transition from the first region to the second region is due to lowering of symmetry. The transition from second to third region is due to magnetic transition, i.e. ferrimagnetic to paramagnetic state. The transition temperatures are nearly equal to the Curie temperatures of the materials. The porosity and activation energy were calculated. It was found that the electrical conductivity is progressively increasing with increase of sintering temperature while the porosity and activation energy decrease continuously. The Seebeck coefficient (Q), carrier concentration (n) and mobility (μ) of charge carriers have been discussed as a function of sintering temperature and temperature.

Role of physical factors in solid : liquid interface formation during oriented eutectic growth

Abstract: The basic physical factors affecting the eutectic interface shape observed in the microscopic scale have been discussed regarding the theory of completely coupled growth. The analysis considers phenomena like: heterogeneous nucleation and growth, interface undercooling of the both eutectic phases, phase protrusion and eventually horizontal temperature gradient. The contribution of the transition layer to the interface shape formation is emphasised.

Influence of crystallisation conditions on the microtexture of the directionally solidified eutectic of the MgF2CaF2 system

Abstract: The influence of high-frequency (HF) and resistive (R) heating of a vertical crystallizer furnace on the directional solidification process of the MgF2CaF2 system eutectic has been compared. The turbulent flow induced by HF heating given rise to inhomogeneities in microtexture, which do not occur under R heating conditions. Variations in the growth rate (v) and temperature gradient (ΔT) lead to characteristic changes of the eutectic microstructure: from lamellar to rod-like. Quantitative analysis of these changes was advantageously performed using a digital image analysis of the area (AR), maximum cross-section (D-MAX), direction of the maximum cross-section (ANGLE D-MAX) of MgF2 particles of the microtexture. This was recorded on SCAN images of transverse cuts through the given directionally solified samples as well as the analysis of the shape of MgF2 particles.