Oxygen-deficient SrTiO3−x, x = 0.28, 0.17, and 0.08. Crystal growth, crystal structure, magnetic, and transport properties

1991 ◽  
Vol 90 (2) ◽  
pp. 320-330 ◽  
Author(s):  
Wenhe Gong ◽  
H. Yun ◽  
Y.B. Ning ◽  
J.E. Greedan ◽  
W.R. Datars ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Transport Properties

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Alkyl-chain disorder in tetraisohexylammonium bromide

2012 ◽  
Vol 68 (4) ◽  
pp. o152-o155 ◽  
Author(s):  
Malcolm A. Kelland ◽  
Amber L. Thompson
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Alkyl Chain ◽  
Growth Inhibitor ◽  
Ammonium Cation ◽  
Asymmetric Unit ◽  
Bromide Anion ◽  
Alkyl Chains ◽  
Hydrate Crystal ◽  
Structure Ii Clathrate Hydrate

Tetraisohexylammonium bromide [systematic name: tetrakis(4-methylpentyl)azanium bromide], C24H52N+·Br−, is a powerful structure II clathrate hydrate crystal-growth inhibitor. The crystal structure, in the space groupP3221, contains one ammonium cation and one bromide anion in the asymmetric unit, both on general positions. At 100 K, the ammonium cation exhibits one ordered isohexyl chain and three disordered isohexyl chains. At 250 K, all four isohexyl chains are disordered. In an effort to reduce the disorder in the alkyl chains, the crystal was thermally cycled, but the disorder remained, indicating that it is dynamic in nature.

scholarly journals Synthesis of magnesium carbonate hydrate from natural talc

2020 ◽  
Vol 18 (1) ◽  
pp. 951-961
Author(s):  
Qiuju Chen ◽  
Tao Hui ◽  
Hongjuan Sun ◽  
Tongjiang Peng ◽  
Wenjin Ding
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Crystal Growth ◽  
Crystal Morphology ◽  
Magnesium Carbonate ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Morphological Transformation ◽  
X Ray ◽  
Carbonation Process

AbstractVarious morphologies of magnesium carbonate hydrate had been synthesized without using any organic additives by carefully adjusting the reaction temperature and time during the talc carbonation process. At lower temperatures, magnesium carbonate hydrate was prone to display needle-like morphology. With the further increase of the carbonation temperature, the sheet-like crystallites became the preferred morphology, and at higher aging temperatures, these crystallites tended to assemble into layer-like structures with diverse morphologies, such as rose-like particles and nest-like structure. The reaction time had no effect on the crystal morphology, but it affected the particle size and situation of the crystal growth. X-Ray diffraction results showed that these various morphologies were closely related to their crystal structure and compositions. The needle-like magnesium carbonate hydrate had a formula of MgCO3·3H2O, whereas with the morphological transformation from needle-like to sheet-like, rose-like, and nest-like structure, their corresponding compositions also changed from MgCO3·3H2O to 4MgCO3·Mg(OH)2·8H2O, 4MgCO3·Mg(OH)2·5H2O, and 4MgCO3·Mg(OH)2·4H2O.

scholarly journals Fabrication, micro-structure characteristics and transport properties of co-evaporated thin films of Bi2Te3 on AlN coated stainless steel foils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aziz Ahmed ◽  
Seungwoo Han
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Thin Films ◽  
Stainless Steel ◽  
Substrate Temperature ◽  
Transport Properties ◽  
Structural Defects ◽  
Film Composition ◽  
High Substrate ◽  
Foil Substrate

AbstractN-type bismuth telluride (Bi2Te3) thin films were prepared on an aluminum nitride (AlN)-coated stainless steel foil substrate to obtain optimal thermoelectric performance. The thermal co-evaporation method was adopted so that we could vary the thin film composition, enabling us to investigate the relationship between the film composition, microstructure, crystal preferred orientation and thermoelectric properties. The influence of the substrate temperature was also investigated by synthesizing two sets of thin film samples; in one set the substrate was kept at room temperature (RT) while in the other set the substrate was maintained at a high temperature, of 300 °C, during deposition. The samples deposited at RT were amorphous in the as-deposited state and therefore were annealed at 280 °C to promote crystallization and phase development. The electrical resistivity and Seebeck coefficient were measured and the results were interpreted. Both the transport properties and crystal structure were observed to be strongly affected by non-stoichiometry and the choice of substrate temperature. We observed columnar microstructures with hexagonal grains and a multi-oriented crystal structure for the thin films deposited at high substrate temperatures, whereas highly (00 l) textured thin films with columns consisting of in-plane layers were fabricated from the stoichiometric annealed thin film samples originally synthesized at RT. Special emphasis was placed on examining the nature of tellurium (Te) atom based structural defects and their influence on thin film properties. We report maximum power factor (PF) of 1.35 mW/m K2 for near-stoichiometric film deposited at high substrate temperature, which was the highest among all studied cases.

scholarly journals Study of anisotropic thermal conductivity in textured thermoelectric alloys by Raman spectroscopy

RSC Advances ◽  
2021 ◽  
Vol 11 (39) ◽  
pp. 24456-24465
Author(s):  
Rapaka S. C. Bose ◽  
K. Ramesh
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Transport Properties ◽  
Thermal Transport ◽  
Layered Crystal ◽  
Layered Crystal Structure ◽  
Thermal Transport Properties ◽  
Anisotropic Thermal Conductivity ◽  
P Type

Polycrystalline p-type Sb1.5Bi0.5Te3 (SBT) and n-type Bi2Te2.7Se0.3 (BTS) compounds possessing layered crystal structure show anisotropic electronic and thermal transport properties.

Crystal growth and transport properties of spin ladder compounds La4+4nCu8+2nO14+8n (n=2, 3)

2001 ◽  
Vol 357-360 ◽  
pp. 380-383 ◽  
Author(s):  
T. Watanabe ◽  
C. Sekar ◽  
H. Shibata ◽  
A. Matsuda ◽  
Y. Zenitani ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Transport Properties ◽  
Spin Ladder

A-Pr2S3, D-Ho2S3 und E-Yb2S3:Synthese und Einkristallstrukturuntersuchungen / A-Pr2S3, D-Ho2S3 and E-Yb2S3:Synthesis and Single Crystal Structure Investigations

1996 ◽  
Vol 51 (5) ◽  
pp. 733-738 ◽  
Author(s):  
Thomas Schleid ◽  
Falk Lissner
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Single Crystals ◽  
Alkali Halides ◽  
Structural Investigations ◽  
Coordination Numbers ◽  
Trivalent Lanthanides ◽  
Trivalent Cations ◽  
Structure Investigations ◽  
Type Orthorhombic

The oxidation of reduced chlorides (MCl2) or chloride-hydrides (MClHx) of the lanthanides with sulfur (700-850 °C, 7 d, sealed tantalum capsules or evacuated silica vessels) usually results in the formation of the sesquisulfides M2S3 as the main products. In the presence of appropriate fluxes (e.g., alkali halides), the products often are obtained as single crystals, and the flux decides which modification is favoured. Ternary halides of the trivalent lanthanides with the corresponding alkali metal can mostly be found as the second components. Crystal growth and structural investigations of thus produced single crystals of Pr2S3 (from PrClH0.67 + S + NaCl, 5:5:1, A type: orthorhombic, Pnma (No. 62), Z = 4, a = 748.22(5), b = 405.51(3), c = 1560.74(9) pm, R = 0.024, Rw = 0.020), Ho2S3, (from U - Ho2S3, + KI, 1:1, D type: monoclinic, P21/m (No. 12), Z = 6, a = 1746.15(9), b = 400.23(3), c = 1012.43(6) pm, β = 98.529(4)°, R = 0.041, Rw = 0.035), and Yb2S3 (from T-Yb2S3 + KI, 1:1, E type: trigonal, R3̄c (No. 167), Z = 6, a = 674.97(2), c = 1820.11(9) pm, R = 0.019, Rw = 0.018) are reported here. In accordance with the lanthanide contraction, the trivalent cations (M3+) exhibit sulfur coordination numbers of 7 and 8 in A -Pr2S3, 6 and 7 in D -Ho2S3, and 6 in E -Yb2S3 (corundum-type structure).

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