scholarly journals Evidence of high-temperature rock salt transformations in areas of occurrence of borate minerals (Zechstein, Kłodawa salt dome, Poland)

2018 ◽  
Author(s):  
Tomasz TOBOŁA ◽  
Jacek WACHOWIAK
Keyword(s):  
High Temperature ◽  
Rock Salt ◽  
Salt Dome ◽  
Borate Minerals

FIXED TRIANGLE IN Bi2-XPbXSr2CaCu2O8+Y AND Bi2-XPbXSr2Ca2Cu3O10+Y SYSTEMS

2013 ◽  
Vol 27 (15) ◽  
pp. 1362015 ◽  
Author(s):  
C. Q. GUO ◽  
C. Y. ZHANG ◽  
S. J. HAO ◽  
W. T. JIN ◽  
H. ZHANG
Keyword(s):  
High Temperature ◽  
Rietveld Refinement ◽  
Chemical Bond ◽  
Rock Salt ◽  
Local Structure ◽  
High Temperature Superconductivity ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Close Relationship

The structural characteristics of Bi 2-x Pb x Sr 2 CaCu 2 O 8+y( Bi -2212) and Bi 2-x Pb x Sr 2 Ca 2 Cu 3 O 10+y( Bi -2223) with x changing from 0 to 0.8 were studied by X-ray diffraction and Rietveld refinement. By careful calculation of chemical bond lengths and angles, it is found that there exists a fixed triangle on the Cu–O planes in the two systems, and then makes the Cu–O planes stable. The fluctuations of this fixed triangle were investigated, and it is found that there is a close relationship between it and Tc's. In addition, we discussed the origin of this special local structure. It may be caused by the interaction between the perovskite block and the rock salt block in a unit cell, which may play an important role in the mechanism of high temperature superconductivity.

Mesoscopic Structures and Their Effects on High-Tc Superconductivity

2017 ◽  
Author(s):  
H. Zhang
Keyword(s):  
High Temperature ◽  
Rock Salt ◽  
High Temperature Superconductors ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Model Calculations ◽  
High Tc ◽  
High Tc Superconductivity ◽  
Electron Phonon Coupling ◽  
Structural Blocks

This article presents the results of model calculations carried out to determine the mesoscopic structural features of high-temperature superconducting (HTS) crystal structures, and especially their characteristic high critical temperature (Tc) and anisotropy. The crystal structure of high-temperature superconductors (HTSc) is unique in having some mesoscopic features. For example, the structures of a majority of cuprite superconductors are comprised of two structural blocks, perovskite and rock salt, stacked along the c-direction. This article calculates the interaction between the perovskite and rock salt blocks in the form of combinative energy in order to elucidate the effects of mesoscopic structures on high-Tc superconductivity. Both X-ray diffraction and Raman spectroscopy show that a ‘fixed triangle’ exists in the samples under investigation. The article also examines the importance of electron–phonon coupling in high-Tc superconductors.

Structural and Electronic Relationships in the High-Temperature Copper-Based Superconductors

1989 ◽  
Vol 156 ◽  
Author(s):  
C.C. Torardi ◽  
D. Jung ◽  
D.B. Kang ◽  
J. Ren ◽  
M.-H. Whangbo
Keyword(s):  
High Temperature ◽  
Copper Oxide ◽  
Fermi Level ◽  
Rock Salt ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Electronic Nature ◽  
Bond Lengths ◽  
Atomic Displacements ◽  
The Ideal

ABSTRACTAtomic displacements from the ideal rock-salt positions in the Tl-, Bi-, and Pb-O layers of the Cu-based high-Tc super-conductors affect the electronic nature of these oxides. When distortions in the Bi-O layers of Bi2Sr2CaCu2O8 are considered, the bottom of the Bi 6p band is found to lie more than 1 eV above the Fermi level. Displacements in the double Tl-O layers of Tl2Ba2Can−1CunO2n+4 places the bottom of the Tl 6s bands significantly below the Fermi level showing that electrons can be removed from the x2-y2 bands of the CuO2 layers. However, this is not the case for the thallium-oxygen single layers of Tl2Ba2Can−1CunO2n+3. Correlations between the superconducting transition temperatures, Tc, and the in-plane Cu-O bond lengths, rCu−O', of the Tl- and Bi- based copper-oxide super-conductors reveal Tc vs rCu−O characteristics similar to those found for La2−xSrxCuO4.

scholarly journals Synthesis of rock-salt MeO–ZnO solid solutions (Me=Ni2+, Co2+, Fe2+, Mn2+) at high pressure and high temperature

2008 ◽  
Vol 28 (4) ◽  
pp. 515-519 ◽  
Author(s):  
A. N. Baranov ◽  
P. S. Sokolov ◽  
O. O. Kurakevych ◽  
V. A. Tafeenko ◽  
D. Trots ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Solid Solutions ◽  
Rock Salt

The Effect of Different Salt Additions on the Microstructure of YBCO Synthesized by a Biomimetic Method

2014 ◽  
Vol 887-888 ◽  
pp. 614-618
Author(s):  
Zi Li Zhang ◽  
Hong Li Suo ◽  
Lin Ma ◽  
Ahmed Kursumovic ◽  
Min Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Rock Salt ◽  
High Temperature Superconductor ◽  
Impurity Content ◽  
Rock Salt Structure ◽  
Granular Microstructure ◽  
Salt Structure ◽  
Biomimetic Method ◽  
Chloride Salts

The effect of different salt additions on the granular microstructure of samples of the high temperature superconductor YBa2Cu3O7δ (YBCO) synthesized by a biomimetic method has been investigated. Attempting biotemplating using salts with the rock-salt structure, most such salts were found to be chemically compatible with the YBCO biosynthesis, but only NaCl and KCl were observed to result in the desirable strongly anisotropic platelet growth to form clusters with localized orientational alignment. Broadening the range of additions to other chloride salts of varying structures resulted in an increase in the CuO impurity content of the samples, but with all the YBCO formed exhibiting platelet growth. Chloride salts are therefore considered to be good candidates for addition to the biomimetic YBCO synthesis in order to achieve anisotropic platelet growth.

scholarly journals Trisodium dicalcium bismuth hexaoxide

2007 ◽  
Vol 63 (3) ◽  
pp. i95-i96 ◽  
Author(s):  
Irina V. Puzdrjakova ◽  
René B. Macquart ◽  
Mark D. Smith ◽  
Hans-Conrad zur Loye
Keyword(s):  
High Temperature ◽  
Single Crystals ◽  
Rock Salt ◽  
Title Compound ◽  
Rock Salt Structure ◽  
Space Group ◽  
Structure Space ◽  
Salt Structure ◽  
Reactive Flux

Single crystals of the title compound, Na3Ca2BiO6, were grown from a high-temperature reactive flux solution of Na2CO3. Na3Ca2BiO6 crystallizes as an ordered rock-salt structure (space group Fddd), in which the octahedral holes in the oxide array are filled by an ordered 3:2:1 arrangement of Na+, Ca2+ and Bi5+ cations. All atoms except for one O atom lie on special positions; site symmetries are as follows: Bi 222, Ca 2, Na 222 and 2, O 2.

SEEING THROUGH ROCK SALT WITH RADAR

Geophysics ◽  
1976 ◽  
Vol 41 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Robert D. Stewart ◽  
Robert R. Unterberger
Keyword(s):  
Shear Zone ◽  
Rock Salt ◽  
Salt Dome ◽  
Salt Mine ◽  
Narrow Beam ◽  
Vhf Radar ◽  
Radar Reflection ◽  
Pure Salt ◽  
Radar Targets

A VHF radar has been used in a salt mine in the Cote Blanche Salt Dome to probe horizontally for the dome flank and vertically for the top of the salt. Discontinuities in the salt's complex electric permitivity caused by anhydrite stringers, shale, sandstone, water, or fractures will caused radar reflections, A narrow beam, ±9 degrees in salt, helps to determine the direction to the discontinuity. The time of the radar reflection determines the range to the discontinuity. The maximum,one‐way penetration was 2040 ft. The radar speed in Cote Blanche salt was measured by timing radar reflections through known distances of salt. The measured radar speed was 188ft/μsec slightly less than the radar speed in pure salt (203 ft/μsec. ). A shear zone in the salt was found to have many discontinuities or radar targets. A discontinuity was detected in a discontinuity about 400 ft above the mine level, but still inside the salt, was also found. The top of the salt dome was detected from several locations in the mine.

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