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Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Etat cristallin (incluant les mouvements moléculaires dans les solides), Crystalline state (including molecular motions in solids), Théorie de la structure cristalline, symétrie cristalline; calculs et modélisation, Theory of crystal structure, crystal symmetry; calculations and modeling, Structure de solides cristallins particuliers, Structure of specific crystalline solids, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Depôt par pulvérisation cathodique, Deposition by sputtering, Aimantation, Magnetization, Aluminate d'yttrium, Yttrium aluminate, Ytrio aluminato, Couche mince, Thin films, Couche épitaxique, Epitaxial layers, Cristallinité, Crystallinity, Cristalinidad, Dépôt physique phase vapeur, Physical vapor deposition, Dépôt pulvérisation, Sputter deposition, Espace réciproque, Reciprocal space, Espacio recíproco, Interface, Interfaces, Mesure magnétique, Magnetic measurement, Medida magnética, Microscopie électronique transmission, Transmission electron microscopy, Propriété symétrie, Symmetry property, Propiedad simetría, Pulvérisation cathodique, Cathode sputtering, Pulvérisation irradiation, Sputtering, Réseau cubique, Cubic lattices, Réseau monoclinique, Monoclinic lattices, Réseau orthorhombique, Orthorhombic lattices, Réseau rhomboédrique, Trigonal lattices, Réseau réciproque, Reciprocal lattice, Red recíproca, Structure cristalline, Crystal structure, Symétrie cristalline, Crystal symmetry, 6150A, 8115C, BiCoO3, BiFeO3, A1. Monoclinic, B1. BiCoO3, B1. BiFeO3, B1. Perovskites, B1. YAlO3 substrates, and B2. Multiferroics

0.9BiFeO3-0.1BiCoO3 (BFCO) films (t= 100 nm) were prepared on orthorhombic YAlO3 (YAO) (100) substrates by r.f. magnetron sputtering. Film flatness, crystallinity, crystal symmetry, and secondary phase formation are strongly affected by the pressure of the sputtering gasses, Ar and O2. Phi-scan measurements showed that the films were epitaxially grown on the substrates, with the crystal relation [101]p(101)p BFCO∥[101]p(101)p YAO. X-ray reciprocal space mapping revealed that the crystal symmetry of the BFCO films was a pseudo-cubic-like monoclinic structure, with Mc phase, rather than the Cm symmetry of the bulk BFCO. Cross-sectional transmission electron microscopy analysis revealed that the film had, as a result of a lattice misfit of 7%, strong compressive strain less than 10 nm from the interface, which relaxed monotonically with increasing distance from the interface. Magnetic measurements show that strained monoclinic BFCO has smaller magnetization compared to rhombohedral BFCO.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Solubilité, ségrégation, mélanges et séparation de phases, Solubility, segregation, and mixing; phase separation, Propriétés de transport (non électroniques), Transport properties of condensed matter (nonelectronic), Diffusion dans les solides, Diffusion in solids, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Croissance en phase fondue; fusion de zone et purification de zone, Growth from melts; zone melting and refining, Diagrammes de phases et microstructures développées par solidification et par transformations de phases solide-solide, Phase diagrams and microstructures developed by solidification and solid-solid phase transformations, Solidification, Contrainte cisaillement, Shear stress, Tensión cizallamiento, Convection naturelle, Natural convection, Croissance cristalline en phase fondue, Crystal growth from melts, Diffusion(transport), Diffusion, Donnée expérimentale, Experimental data, Ecoulement fluide, Fluid flow, Etude théorique, Theoretical study, Interface, Interfaces, Loi échelle, Scaling laws, Modélisation, Modelling, Méthode phase fondue, Growth from melt, Método fase fundida, Simulation numérique, Digital simulation, Simulation ordinateur, Computerized simulation, Solidification dirigée, Directional solidification, Ségrégation, Segregation, Transfert chaleur, Heat transfer, Transfert masse, Mass transfer, 8110F, 8130F, A1. Convection, A1. Directional solidification, A1. Segregation, and A2. Growth from melt

The effect of natural convection on solute segregation in the horizontal Bridgman configuration is studied. The objective is to check whether a single non-dimensional number, based on the fluid flow induced interface shear stress, is able to capture the physics of the mass transport phenomena. A number of heat and mass transfer numerical simulations are carried out in the laminar convection regime, and the segregation results are found to be in good agreement with the predictions of the scaling analysis. At the higher convective levels relevant for the comparison with existing experimental data, a direct computation of the segregation phenomena is not possible, but numerical simulations accounting for turbulence modeling can provide the interface shear stress. With this procedure, a good agreement between the experimentally measured segregation and the predictions of the scaling analysis is again observed, thus validating the choice of the interface shear stress as a key parameter for the segregation studies.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Etudes générales des transformations de phases, General studies of phase transitions, Nucléation, Nucleation, Solubilité, ségrégation, mélanges et séparation de phases, Solubility, segregation, and mixing; phase separation, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Croissance en solution, Growth from solutions, Composé du lithium, Lithium compounds, Croissance cristalline en solution, Crystal growth from solutions, Croissance cristalline, Crystal growth, Dislocation, Dislocations, Energie interface, Interface energy, Energía interfase, Energie libre, Free energy, Etat métastable, Metastable states, Gravure, Etching, Monocristal, Monocrystals, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Méthode en solution, Growth from solution, Método en solución, Nucléation, Nucleation, Perfection cristalline, Crystal perfection, Perfección cristalina, Période induction, Induction period, Período inducción, Solubilité, Solubility, Taux croissance, Growth rate, 6460Q, 8110A, A1. Etching, A1. Nucleation, A1. Single crystal growth, A2. Growth from solutions, and B1. Lithium compounds

Nucleation and growth kinetics give valuable information about the crystal growth process, which can be employed in the growth of large size crystals. Accordingly, this paper discusses nucleation theory as applied to crystallizing negative solubility lithium sulphate monohydrate (LSMH) crystal. Solubility, metastable zone and induction period values were determined experimentally in order to optimize the growth parameters. The nucleation parameters such as interfacial energy, volume free energy, critical free energy and critical radius have been evaluated. The results have been discussed in detail. The good quality single crystal of LSMH was grown by the low temperature solution growth technique. The growth and dislocation behaviors were detected under the etching studies. It is shown that the classical approach explains the available nucleation data under most conditions used for growing LSMH crystals.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structure et morphologie de couches minces, Thin film structure and morphology, Structure et morphologie; épaisseur, Structure and morphology; thickness, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Autres matériaux, Other materials, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Epitaxie en phase vapeur; croissance en phase vapeur, Vapor phase epitaxy; growth from vapor phase, Composé du bismuth, Bismuth compounds, Composé organométallique, Organometallic compounds, Condition opératoire, Operating conditions, Condición operatoria, Couche mince, Thin films, Couche tampon, Buffer layer, Capa tampón, Croissance film, Film growth, Diffraction RX, XRD, Diffusion mutuelle, Interdiffusion, Difusión mútua, Dépendance température, Temperature dependence, Epaisseur couche, Layer thickness, Espesor capa, Epitaxie phase vapeur, VPE, Magnétorésistance, Magnetoresistance, Microscopie force atomique, Atomic force microscopy, Microscopie optique, Optical microscopy, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Méthode MOVPE, MOVPE method, Método MOVPE, Propriété électronique, Electronic properties, Propiedad electrónica, Réflexion RX, X-ray reflection, Semiconducteur II-VI, II-VI semiconductors, Solution solide, Solid solutions, 6855J, 8105L, 8110A, 8115K, Bi2Te2Se, Bi2Te3-xSex, Substrat Al2O3, Substrat métal, A1. Atomic force microscopy, A1. Solid solutions, A1. X-ray diffraction, A3. Metalorganic vapor phase epitaxy, B1. Bismuth compounds, and B2. Semiconducting materials

We report on a metal organic vapor epitaxy (MOVPE) of Bi2Te3-xSex films over the entire range of compositions (0≤x≤3) for the first time. The films were grown on Al2O3(0001) substrates at 465 C using trimethylbismuth (Bi2Me3), diethyltellurium (Et2Te) and diisopropylselenium (iPro2Se) as metalorganic sources. To realize the 2D growth mode and to grow films with flat surfaces and high crystalline quality, a thin ZnTe buffer layer was used. As-grown films were studied using optical and AFM microscopy techniques and X-ray diffraction. It was found that under steady growth conditions the composition of Bi2Te3-xSex films strongly depends on the film thickness. But a high rate of interdiffusion of chalcogens at the growth temperature rapidly leads to a homogeneous composition of the film in the growth direction. Dependence of the intensity of X-ray reflection (0012) on the composition of Bi2Te3-xSex films x has extremes near x = 1 (Bi2Te2Se) and x=2 (Bi2Se2Te). The AFM micrographs and profiles show large (above 2 μm) triangle-shaped atomically flat terraces with step height of a quintuple layer (0.90 nm) of the tetradymite-type compounds. The electronic properties of the grown films have been characterized via four probe magnetotransport measurements.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Etudes générales des transformations de phases, General studies of phase transitions, Nucléation, Nucleation, Transformations de phases particulières, Specific phase transitions, Transformations solide-solide, Solid-solid transitions, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Points quantiques, Quantum dots, Divers, Other topics in nanoscale materials and structures, Acétone, Acetone, Cristallisation, Crystallization, Croissance cristalline, Crystal growth, Cyclodextrine, Cyclodextrin, Ciclodextrina, Matériau composite, Composite materials, Méthode en solution, Growth from solution, Método en solución, Nanomatériau, Nanostructured materials, Nucléation, Nucleation, Point quantique, Quantum dots, 6460Q, 6470K, 8107T, CdS, A1. Low dimensional structures, A1. Nucleation, A2. Growth from solution, and B1. Oxides

Inorganic molecules have seldom been included into cyclodextrin crystal. Here in this paper we report the first example of including CdS quantum dots into cyclodextrin crystal by simple rapid crystallization. A CdS quantum dot/cyclodextrin composite has been obtained, in which quantum dots of CdS are embedded in β-cyclodextrin (β-CD) crystal. Experiments have proven that it is the rapid crystallization of cyclodextrin in acetone that results in the formation of abundant cyclodextrin nuclei, which include CdS dots into them forming the CdS quantum dot/cyclodextrin compostie. This research opens the new research field of inorganic species/cyclodextrin inclusion complex.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Etudes générales des transformations de phases, General studies of phase transitions, Nucléation, Nucleation, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Matériaux poreux; matériaux granulaires, Porous materials; granular materials, Angle contact, Contact angle, Chlorure de sodium, Sodium chloride, Sodio cloruro, Germination hétérogène, Heterogeneous nucleation, Germinación heterogénea, Glace, Ice, Matériau poreux, Porous materials, Nucléation, Nucleation, Structure pores, Pore structure, Estructura poros, 6460Q, 8105R, NaCl, A1. Characterization, A1. Contact angle, A1. Nucleation, and B1. Sodium chloride

Clarifying the nucleation process of chloride-based deicing salt solution (e.g., NaCl solution) confined in cement-based porous materials remains an important issue to understand its detrimental effects on material substrates. In this study, the pore structures of hardened cement pastes were characterized by mercury-intrusion and nitrogen-sorption porosimetry. The ice nucleation temperature of NaCl solution of different concentrations confined in the hardened cement pastes was measured and analyzed by classical heterogeneous nucleation theory. The kinetic factor, contact-angle factor including the contact angle between ice and the substrate were evaluated. The results revealed that the contact angle between ice and the substrate showed the minimum value when adding 3% NaCl into water. The heterogeneous ice nucleation rates were found to be proportional to the water activity shifts.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Structure de solides cristallins particuliers, Structure of specific crystalline solids, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Croissance en phase fondue; fusion de zone et purification de zone, Growth from melts; zone melting and refining, Condition opératoire, Operating conditions, Condición operatoria, Cristal hexagonal, Hexagonal crystals, Croissance cristalline en phase fondue, Crystal growth from melts, Diffraction Laue, Laue diffraction, Difracción Laue, Microscopie force atomique, Atomic force microscopy, Monocristal, Monocrystals, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Paroi domaine, Domain walls, Perfection cristalline, Crystal perfection, Perfección cristalina, Propriété électronique, Electronic properties, Propiedad electrónica, Réseau hexagonal, Hexagonal lattices, Structure cristalline, Crystal structure, Zone flottante, Floating zone, Zona flotante, 8110A, 8110F, ErMnO3, Floating-zone technique, Hexagonal manganite, and Multiferroic crystals

Hexagonal manganites are among the most intensively studied multiferroics, exhibit unusual geometrically driven ferroelectricity and magnetoelectric couplings, and form domains and domain walls with intriguing functional properties. In order to study these electronic correlation phenomena and develop a comprehensive understanding about the underlying physics, the availability of high-quality single-crystals is crucial. In particular, different members of the RMnO3 (R=Sc, Y, In, Dy to Lu) family require different growth condition in order to achieve stoichiometric single-phase crystals. Here, we report on the growth of high-quality ErMnO3 single crystals with dimensions of 5 mm in diameter and up to 60 mm in length using the pressurized floating-zone technique. We present Laue diffraction, piezo-response force microscopy, and conductive atomic force microscopy data, reflecting the quality of our single crystals regarding the structure, as well as electronic properties on the level of domains and domain walls.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés thermiques, Thermal properties of condensed matter, Propriétés thermiques des solides cristallins, Thermal properties of crystalline solids, Dilatation thermique ; effet thermomécanique et densité, Thermal expansion; thermomechanical effects and density, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux diélectriques, piézoélectriques et ferroélectriques, Dielectrics, piezoelectrics, and ferroelectrics and their properties, Matériaux diélectriques, piézoélectriques, ferroélectriques et antiferroélectriques, Dielectric, piezoelectric, ferroelectric and antiferroelectric materials, Niobates, titanates, tantalates, céramiques pzt, etc, Niobates, titanates, tantalates, pzt ceramics, etc, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Croissance en solution, Growth from solutions, Croissance cristalline en solution, Crystal growth from solutions, Ferroélectrique, Ferroelectric materials, Material ferroeléctrico, Matériau piézoélectrique, Piezoelectric materials, Monocristal, Monocrystals, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Méthode TSSG, TSSG method, Método TSSG, Niobate, Niobates, Point Curie, Curie point, Propriété thermique, Thermal properties, Réseau cubique, Cubic lattices, Réseau quadratique, Tetragonal lattices, Stabilité thermique, Thermal stability, Température transition, Transition temperature, Transition phase, Phase transitions, Transición fase, 6540D, 8110A, 8110D, A2. Top-seeded solution growth, B1. Niobates, B1. Perovskite, and B2. Piezoelectric materials

In this work, a large size lead-free piezoelectric single crystal, (K,Na,Li)(Nb,Ta,Sb)O3 (KNLNTS) with the dimensions of 8.5 × 8.5 × 13.5 mm3 was successfully grown by the top-seeded solution growth method. This KNLNTS single crystal with high compositional homogeneity is in the tetragonal phase at room temperature. The Curie temperature Tc of the tetragonal-cubic phase transition temperature is 210 C. The piezoelectric coefficients and electromechanical coupling factors of the [001]c oriented KNLNTS single crystal are d33=172.55 pC/N, d31 = -71.90 pC/N, k31 =0.327, k33=0.523, and kt=0.541. In addition, the crystal shows good thermal stability so that it can be used for making high temperature electromechanical devices.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés de transport (non électroniques), Transport properties of condensed matter (nonelectronic), Diffusion dans les solides, Diffusion in solids, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Epitaxie en phase vapeur; croissance en phase vapeur, Vapor phase epitaxy; growth from vapor phase, Adatome, Adatoms, Composé III-V, III-V compound, Compuesto III-V, Couche mince, Thin films, Couche épitaxique, Epitaxial layers, Densité dislocation, Dislocation density, Diffusion(transport), Diffusion, Dislocation coin, Edge dislocations, Epitaxie phase vapeur, VPE, Face cristalline, Crystal faces, Hydrure, Hydrides, Microscopie force atomique, Atomic force microscopy, Morphologie surface, Surface morphology, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Nitrure, Nitrides, Réseau hexagonal, Hexagonal lattices, Semiconducteur III-V, III-V semiconductors, Structure dislocation, Dislocation structure, Structure surface, Surface structure, 8110A, 8115K, A1. AFM, A1. AlN, A1. Surface morphology, and A3. HVPE

The evolution of the surface morphologies of AIN films grown by hydride vapor phase epitaxy (HVPE) was studied using atomic force microscopy (AFM). Our results indicate that, after an initial growth time of 10 min, the surface is dominated by hexagonal-prism-shaped islands. Dislocation mediated surface structures of spiral hillocks are observed to cover the surface when the growth time extends to 1 h. Upon further extending the growth time to 3 h, the typical surface morphologies change and the density of dislocation decreases by one order. We also discuss the relationship between the diffusion behaviors of adatoms on the crystal surface with the shape of the terrace edges around dislocations. Explorations into the evolution of the surface morphology of AlN epitaxial films are crucial for understanding the origin and subsequent annihilation of dislocations, as well as to promote improved dislocation reduction techniques for III-nitride materials.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Etudes générales des transformations de phases, General studies of phase transitions, Nucléation, Nucleation, Transformations de phases particulières, Specific phase transitions, Transformations solide-solide, Solid-solid transitions, Solubilité, ségrégation, mélanges et séparation de phases, Solubility, segregation, and mixing; phase separation, Propriétés thermiques, Thermal properties of condensed matter, Propriétés thermiques des solides cristallins, Thermal properties of crystalline solids, Propriétés thermodynamiques, Thermodynamic properties, Barrière énergie, Energy barrier, Barrera energía, Cristallisation, Crystallization, Croissance cristalline, Crystal growth, Dihydrogénophosphate de potassium, KDP, Décomposition thermique, Thermal decomposition, Descomposición térmica, Energie activation, Activation energy, Energie interface, Interface energy, Energía interfase, Energie libre Gibbs, Gibbs free energy, Energía libre Gibbs, Energie libre, Free energy, Enthalpie, Enthalpy, Entropie, Entropy, Gravimétrie, Gravimetry, Méthode en solution, Growth from solution, Método en solución, Nucléation, Nucleation, Phosphate de potassium, Potassium phosphate, Potasio fosfato, Propriété thermodynamique, Thermodynamic properties, Solubilité, Solubility, Sulfate, Sulfates, Thermogravimétrie, Thermogravimetry, 6460Q, 6470K, 6540G, A1. Nucleation, A1. Solubility, A2. Growth from solutions, B3. Non linear, and Optic materials

This work elevates the relevance of kinetic parameters of nucleation and thermal decomposition for water soluble crystals. The positive soluble Potassium Dihydrogen Phosphate (KDP) and negative soluble Lithium Sulfate Monohydrate (LSMH) materials were chosen for the kinetic evaluation. The results obtained from the classical nucleation theory are verified with the kinetic parameters which are evaluated from thermo gravimetric analysis. Nucleation parameters of a crystallization process such as interfacial energy (σ), volume free energy (ΔGv), critical energy barrier for nucleation (ΔG*), radius of the critical nucleus (r*) and nucleation rate (J) of the positive (KDP) and negative solubility (LSMH) crystals are determined from the classical nucleation theory of solubility-enthalpy relation. The kinetic parameters viz. the order of reaction, enthalpy, Gibbs free energy of activation, frequency factor, and entropy of activation are obtained from the TG based models viz. Horowitz-Metzger, Coats-Redfern and Piloyan-Novikova. The effect of varying temperature with relative variation on Gibbs free energy for both positive and negative solubility crystals is also discussed. The developed model holds good for both positive and negative solubility crystals.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Etudes générales des transformations de phases, General studies of phase transitions, Nucléation, Nucleation, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structure et morphologie de couches minces, Thin film structure and morphology, Structure et morphologie; épaisseur, Structure and morphology; thickness, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Epitaxie par faisceaux chimiques, ioniques, atomiques et moléculaires, Molecular, atomic, ion, and chemical beam epitaxy, Accommodation réseau, Mismatch lattice, Acomodación red, Condition opératoire, Operating conditions, Condición operatoria, Couche mince, Thin films, Dépendance température, Temperature dependence, Effet contrainte, Stress effects, Epaisseur couche, Layer thickness, Espesor capa, Epitaxie jet moléculaire, Molecular beam epitaxy, Hétéroépitaxie, Heteroepitaxy, Heteroepitaxia, Morphologie cristalline, Crystal morphology, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Mécanisme formation, Formation mechanism, Mecanismo formacion, Méthode Monte Carlo, Monte Carlo methods, Nucléation, Nucleation, Simulation ordinateur, Computerized simulation, Valeur critique, Critical value, Valor crítico, 6460Q, 6855J, 8110A, 8115H, A1. Computer simulation, A1. Crystal morphology, A1. Nucleation, A1. Stresses, and A3. Molecular beam epitaxy

We use a two-dimensional ball and spring model to model a heteroepitaxial system using fast kinetic Monte Carlo simulations. Effects of deposition flux, lattice mismatch, and growth temperature on the morphology of film surfaces are studied in detail. The two strain-relieve mechanisms, island formation and pit formation are investigated. We find the formation of islands at large lattice mismatch and high growth temperature, in agreement with the island nucleation theory. In limited mobility growth at high deposition flux, the formation of pits is found to be more preferable. The increase in the lattice mismatch leads to the decrease of critical thickness and island size. These values, however, are also significantly affected by growth conditions. Increasing the deposition flux results in larger critical thickness and smaller island size while higher growth temperature causes the critical thickness to be smaller but island size becomes larger.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Défauts et impuretés dans les cristaux; microstructure, Defects and impurities in crystals; microstructure, Défauts linéaires: dislocations, disinclinaisons, Linear defects: dislocations, disclinations, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Etudes générales des transformations de phases, General studies of phase transitions, Nucléation, Nucleation, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Epitaxie par faisceaux chimiques, ioniques, atomiques et moléculaires, Molecular, atomic, ion, and chemical beam epitaxy, Composé III-V, III-V compound, Compuesto III-V, Couche autoportée, Free-standing film, Couche monomoléculaire, Monolayers, Couche épitaxique, Epitaxial layers, Dislocation filetée, Threading dislocation, Dislocación aterrajada, Décharge haute fréquence, High-frequency discharges, Désorption, Desorption, Epitaxie jet moléculaire, Molecular beam epitaxy, Microstructure, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Nitrure, Nitrides, Nucléation, Nucleation, Semiconducteur III-V, III-V semiconductors, Traitement par plasma, Plasma assisted processing, 6172L, 6460Q, 8110A, 8115H, GaN, Substrat GaN, A1. Defects, A1. Impurities, A3. Molecular beam epitaxy, B1. Nitrides, and N-polar nitrides

We have investigated the microstructure of homoepitaxial N-polar GaN layers grown by rf-plasma-assisted molecular beam epitaxy on freestanding GaN substrates. The structural quality of the epitaxial layers improves when the sheet density of oxygen present on the substrate surface diminishes. An initial sheet density of oxygen of ~0.5 monolayer (ML) results in a highly defective epitaxial layer, while an epitaxial layer with no visible threading dislocations was grown on a substrate with an initial oxygen sheet density of ~0.08 ML. The significant reduction in oxygen was achieved by using several cycles of Ga deposition and thermal desorption prior to the start of epitaxial growth combined with an initial ultrathin 15-Å AlN nucleation layer. These results indicate that reducing the density of oxygen on the surfaces of freestanding N-polar GaN substrates is vital for obtaining high quality homoepitaxial N-polar GaN layers.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés de transport (non électroniques), Transport properties of condensed matter (nonelectronic), Diffusion dans les solides, Diffusion in solids, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Dépôt chimique en phase vapeur (incluant le cvd activé par plasma, mocvd, etc.), Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.), Epitaxie en phase vapeur; croissance en phase vapeur, Vapor phase epitaxy; growth from vapor phase, Basse pression, Low pressure, Composé III-V, III-V compound, Compuesto III-V, Couche contrainte, Strained layer, Capa forzada, Diffusion(transport), Diffusion, Dépendance température, Temperature dependence, Désorption, Desorption, Epitaxie phase vapeur, VPE, Etude théorique, Theoretical study, Indium, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Méthode MOCVD, MOCVD, Méthode MOVPE, MOVPE method, Método MOVPE, Nitrure, Nitrides, Semiconducteur III-V, III-V semiconductors, Taux croissance, Growth rate, 8110A, 8115G, 8115K, GaN, InGaN, Substrat GaN, Substrat saphir, Growth models, Metalorganic vapor phase epitaxy, and Semiconducting III-V materials

InGaN strained bulk layers were grown by low-pressure metalorganic chemical vapor deposition on c-plane GaN/sapphire templates. Two growth regimes, mass-transport limited regime and indium desorption regime, were examined for InGaN growth. In the indium desorption regime, more indium source must be fed to keep a constant indium content. In the indium desorption regime, we found an abnormally enhanced GaN growth rate, which was proved to be related to the indium desorption and dependent on the growth temperature and the indium source flow. Due to the enhanced growth rate, the optical quality of In0.16Ga0.84N layers degraded significantly.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des solides, Mechanical properties of solids, Elasticité, constantes d'élasticité, Elasticity, elastic constants, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Diagrammes de phases et microstructures développées par solidification et par transformations de phases solide-solide, Phase diagrams and microstructures developed by solidification and solid-solid phase transformations, Transformations martensitiques, Martensitic transformations, Alliage mémoire forme, Shape memory alloy, Aleación memoria forma, Diffraction RX, XRD, Essai compression, Compressive testing, Essai traction, Tensile tests, Fil métallique, Wire, Hilo metálico, Module Young, Young modulus, Monocristal, Monocrystals, Métal transition alliage, Transition element alloys, Nickel alliage, Nickel alloys, Orientation cristalline, Crystal orientation, Polycristal, Polycrystals, Rayonnement synchrotron, Synchrotron radiation, Recuit, Annealing, Relation contrainte déformation, Stress-strain relations, Superélasticité, Superelasticity, Texture, Titane alliage, Titanium alloys, Transformation martensitique, Martensitic transformations, Analyse mécanique dynamique, Dynamic mechanical analysis, mechanical, modeling and simulation, and non-ferrous metals

Young's moduli of superelastic NiTi wires in austenite and stress-induced martensite states were evaluated by three different experimental methods (tensile tests, in situ synchrotron x-ray diffraction, and dynamic mechanical analysis) and estimated via theoretical calculation from elastic constants. The unusually low value of the Young's modulus of the martensite phase appearing in material property tables ( < 40 GPa) is generally ascribed in the literature to the fact that stress-driven martensitic transformation and/or twinning processes continue even beyond the transformation range and effectively decrease the value of the tangent modulus evaluated from macroscopic stress-strain curve. In this work, we claim that this low value is real in the sense that it corresponds to the appropriate combination of elastic constants of the B19' martensite phase forming the polycrystalline wire. However, the Young's modulus of the martensite phase is low only for wire loaded in tension, not for compression or other deformation modes. It is shown that the low value of the martensite Young's modulus in tension is due to the combination of the unique coincidence of elastic anisotropy of the B19' martensite characterized by the low elastic constant C55, austenite drawing texture, and strong martensite texture due to the martensite variant selection under tensile stress.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des solides, Mechanical properties of solids, Elasticité, constantes d'élasticité, Elasticity, elastic constants, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Diagrammes de phases et microstructures développées par solidification et par transformations de phases solide-solide, Phase diagrams and microstructures developed by solidification and solid-solid phase transformations, Transformations martensitiques, Martensitic transformations, Biomatériau, Biomedical materials, Composé intermétallique, Intermetallic compounds, Contrainte interne, Internal stresses, Diffraction RX, XRD, Distribution contrainte, Stress distribution, Endodontie, Endodontic procedures, Endodoncia, Essai flexion, Bending test, Ensayo flexion, Métal transition alliage, Transition element alloys, Méthode élément fini, Finite element method, Nickel alliage, Nickel alloys, Rayonnement synchrotron, Synchrotron radiation, Spectre SIMS, Secondary ion mass spectra, Titane alliage, Titanium alloys, Transformation martensitique, Martensitic transformations, advanced characterization, biomaterial, and intermetallic

Two types of endodontic files (ProFile and Mtwo) were studied in order to analyze the effect of geometry on the stress-induced martensitic (SIM) transformation during bending. The use of a fine beam spot of synchrotron radiation allowed a detailed structural characterization with a fine spatial resolution. Experimental evidence of the effect of the cross-section geometry on the stress localization giving rise to different degrees of SIM transformation is presented for the first time in the published literature.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Structure de solides cristallins particuliers, Structure of specific crystalline solids, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structure et morphologie de couches minces, Thin film structure and morphology, Composition et identification des phases, Composition and phase identification, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Théorie et modèles de la croissance de films, Theory and models of film growth, Article synthèse, Reviews, Cristal moléculaire, Molecular crystals, Cristallographie RX, X-ray crystallography, Diffraction RX, XRD, Dioxyde de carbone, Carbon dioxide, Carbono dióxido, Effet pression, Pressure effects, Haute pression, High pressure, Haute température, High temperature, Alta temperatura, Monocristal, Monocrystals, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Phase cristalline, Crystalline phase, Fase cristalina, Rayonnement synchrotron, Synchrotron radiation, Structure cristalline, Crystal structure, Transformation phase, Phase transformations, Transition phase, Phase transitions, Transición fase, 6855A, 6855N, 8110A, high pressure crystallography, simple molecular solids, solid carbon dioxide, solid oxygen, and structural phase transition

A review of recently developed methods to study the structural properties of simple molecular solids under pressures up to the megabar range using synchrotron X-ray diffraction techniques is presented. This includes the growth of single-crystals at high pressure and temperature conditions and the use of He as pressure-transmitting medium. The application of these methods to solid O2 and CO2 is then presented as illustrative examples, showing how they enabled to solve long-standing debates on the structure of the high-pressure crystalline phases of these compounds.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des solides, Mechanical properties of solids, Déformation et plasticité (incluant limite élastique, ductilité et superplasticité), Deformation and plasticity (including yield, ductility, and superplasticity), Alliage mémoire forme, Shape memory alloy, Aleación memoria forma, Alliage équiatomique, Equiatomic alloy, Aleación equiatómica, Composé intermétallique, Intermetallic compounds, Cycle thermique, Thermal cycle, Ciclo térmico, Effet mémoire forme, Shape memory effects, Nickel alliage, Nickel alloys, Plasticité, Plasticity, Titane alliage, Titanium alloys, Traitement thermique, Heat treatments, aerospace, energy, and intermetallic

The influence of thermal cycling under a symmetric scheme for work performance on the functional properties and work output of equiatomic TiNi shape memory alloys was studied. It was found that the Ti50Ni50 alloy produced an effective work output of 9.7 MJ/m3 and an efficiency of 1.47% in a symmetrical scheme for work production where the stress acting on cooling was 50 MPa, and the stress acting on heating was 200 MPa. It was observed that the Ti50Ni50 alloy demonstrated the monotonic dependence of plastic strain on the number cycle, and 3.1% of the residual strain was accumulated over 30 cycles. The data have shown that using a 'symmetric' scheme for work production allows one to reduce a plastic strain 13-fold in comparison with an 'asymmetric' scheme. Thus, the symmetric scheme for work production provides for the high stability of the functional properties and work output of TiNi-based shape memory alloys.