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The lithium niobate–lithium tantalate solid solution's phase diagram was investigated using experimental data from differential thermal analysis (DTA) and crystal growth. We used XRF analysis to determine the elemental composition of the crystals. The Neumann–Kopp rule provided essential data for the end members lithium niobate (LN) and lithium tantalate (LT). The heats of fusion of the end members, given by DTA measurements, are 103 kJ/mol at 1531 K for LN and 289 kJ/mol at 1913 K for LT. These values were used as input parameters to generate the data. This data served as the basis for calculating a phase diagram for LN-LT solid solutions. Finally, based on the experimental data and a thermodynamic solution model, the Calphad Factsage module optimized the phase diagram. We also generated thermodynamic parameters for Gibbs' excess energy of the solid solution. A plot of the segregation coefficient as a function of Ta concentration was derived from the phase diagram. [ABSTRACT FROM AUTHOR]

By differential thermal analysis, a concentration field suitable for the growth of Zr, Mg co-doped strontium hexagallate crystals was observed that corresponds well with known experimental results. It was shown that the melting point of doped crystal is ca. 60 K higher than that of undoped crystals. This higher melting points indicate hexagallate phase stabilization by Zr, Mg co-doping and increase the growth window of (Mg,Zr):SrGa12O19, compared to undoped SrGa12O19 that grows from SrO–Ga2O3 melts. [ABSTRACT FROM AUTHOR]

Cubic rare‐earth sesquioxide crystals are strongly demanded host materials for high power lasers, but due to their high melting points investigations on their thermodynamics and the growth of large‐size crystals of high optical quality remain a challenge. Detailed thermal investigations of the ternary system Lu2O3–Sc2O3–Y2O3 revealing a large range of compositions with melting temperatures below 2200°C and a minimum of 2053°C for the composition (Sc0.45Y0.55)2O3 are presented. These reduced temperatures enable for the first time the growth of high optical quality mixed sesquioxide crystals with disordered structure by the conventional Czochralski method from iridium crucibles. An (Er0.07Sc0.50Y0.43)2O3 crystal is successfully grown and characterized with respect to its crystallographic properties as well as its composition, thermal conductivity and optical absorption in the 1 µm range. [ABSTRACT FROM AUTHOR]

By differential thermal analysis (DTA) is was shown that the pseudo-binary system Tb 2 O 3 –SiO 2 contains intermediate compounds Tb 2 SiO 5 , Tb 4 Si 3 O 12 and Tb 2 Si 2 O 7. All three compounds melt congruently, a phase diagram was proposed, and from the latter compound single crystals could be grown for the first time. This was possible from stoichiometric feed rods by the optical floating-zone (OFZ) technique. X-ray powder analysis proved the Pna 2 1 phase of the crystals. Melting temperature and heat of fusion were measured by DTA to be 1769◦C and ≈ 150 kJ/mol, respectively. The specific heat capacity of Tb 2 Si 2 O 7 was measured by dynamic DSC to be c p ​= ​149.4982 ​+ ​0.2242 ⋅ T − 7.3913 ​× ​10−5 ⋅ T 2 + 558449.3624 ⋅ T −2. [Display omitted] • Tb 2 O 3 –SiO 2 phase diagram contains three phases – all melt congruently. • Tb 2 Si 2 O 7 single crystal (space group Pna 2 1) grown for the first time. • basic thermal characterization (c p , heat of and temperature of fusion) performed. [ABSTRACT FROM AUTHOR]

The TiO2 rich part of the (1 - x)SrO + xTiO2 phase diagram (0.5 ⩽ x ⩽ 1.0) was redetermined and the eutectic point between SrTiO3 and TiO2 was found at xeut = 0.7700 ± 0.0001; Teut = 1449 ± 3 °C. From TiO2 rich melt solutions, x = 0.75, centimeter-sized single crystals could be grown. The best crystals with an etch pit density of <2 × 104 cm-2 were obtained for growth directions (110) and (100). AFM investigation of the interface reveals layer-by-layer growth. [ABSTRACT FROM AUTHOR]

Abstract: Small ruby crystals were grown by the Czochralski technique in different atmospheres and their actual chromium content was analyzed by a wet chemical method. The chromium distribution coefficient k was found to be strongly dependent on oxygen partial pressure . It ranges from k=0.3 in a reducing atmosphere to k=1.2 in a slightly oxidizing atmosphere and to a good approximation k depends linearly on . The experimental data are discussed on the basis of thermodynamic equilibrium calculations. [Copyright &y& Elsevier]

Abstract: DTA measurements with mixtures of aluminum oxide and lutetium oxide around the perovskite composition were performed up to . A peak with onset was due to the melting of the eutectic (monoclinic phase) and (perovskite). Neither peritectic melting of the perovskite nor its decomposition in the solid phase could be resolved experimentally. The maximum of the eutectic peak size is near , on the Lu-rich side of the perovskite, which is consistent with the conclusion that melts peritectically at ca. as proposed by Wu, Pelton, J. Alloys Compd. 179 (1992) 259. Thermodynamic equilibrium calculation reveals that under strongly reducing conditions (oxygen partial pressure ) aluminum(III) oxide can be reduced to suboxides or even Al metal. It is shown that under such conditions a new phase field with liquid Al can appear. [Copyright &y& Elsevier]

Cubic rare‐earth sesquioxide crystals are strongly demanded host materials for high power lasers, but due to their high melting points investigations on their thermodynamics and the growth of large‐size crystals of high optical quality remain a challenge. Detailed thermal investigations of the ternary system Lu2O3–Sc2O3–Y2O3 revealing a large range of compositions with melting temperatures below 2200°C and a minimum of 2053°C for the composition (Sc0.45Y0.55)2O3 are presented. These reduced temperatures enable for the first time the growth of high optical quality mixed sesquioxide crystals with disordered structure by the conventional Czochralski method from iridium crucibles. An (Er0.07Sc0.50Y0.43)2O3 crystal is successfully grown and characterized with respect to its crystallographic properties as well as its composition, thermal conductivity and optical absorption in the 1 µm range. [ABSTRACT FROM AUTHOR]

Highlights • Crystal growth between NdLuO 3 and NdScO 3 from the melt is performed. • From NdScO 3 rich melts perovskite type crystals are obtained. • Perovskite phase in the subsolidus is stable for almost arbitrary composition. • Liquidus projection of the Nd 2 O 3 –Lu 2 O 3 –Sc 2 O 3 ternary is presented. Abstract Based on differential thermal analysis (DTA) and X-ray powder diffraction (XRD), a description of the Nd 2 O 3 –Lu 2 O 3 –Sc 2 O 3 system was obtained by thermodynamic assessment. Four fields of primary crystallization could be identified; from melt compositions close to the Lu 2 O 3 –Sc 2 O 3 edge, the rare-earth oxide C-phase crystallizes first which is stable down to room temperature. From Nd 2 O 3 rich melts, the X-phase forms which is stable only at high temperatures. An additional field, where the alternative high-temperature phase H solidifies as primary product touches the Nd 2 O 3 –Lu 2 O 3 edge of the concentration triangle. From melts close to the composition NdScO 3 , the P-phase (perovskite) can be crystallized and mixed crystals with second endmember NdLuO 3 have been grown from the melt. Crystals of this mixed perovskite were grown by the micro-pulling-down and Czochralski methods. [ABSTRACT FROM AUTHOR]

The pseudobinary system LaLuO 3 –LaScO 3 was explored in hopes of discovering new perovskite-type substrates with pseudocubic lattice parameters above 4 Å. A complete solid solution of the type (LaLuO 3 ) 1− x (LaScO 3 ) x forms between the end members LaLuO 3 and LaScO 3 , enabling large single crystals of (LaLuO 3 ) 1− x (LaScO 3 ) x to be grown from the melt. A single crystal with x ≈0.34 was demonstrated. Considering the maximum thermal load of the iridium crucibles appropriate for Czochralski growth of this solid solution, the theoretically maximum achievable x -value is ~0.67. Based on the phase diagram determined, it is anticipated that single crystals with pseudocubic lattice constants between 4.09 and 4.18 Å can be grown in this system by the Czochralski method. [ABSTRACT FROM AUTHOR]