High-temperature superconducting

CUO2 layers appear in all cuprate superconductors and appear to be a necessary but not sufficient condition for high temperature superconduction. The La2SrCu20g 2 compound has CUO2 layers but does not superconduct. Experiments also indicate that T is proportional to the carrier density in the CUO2 layer but not to the volume carrier density, which is further evidence that the YBa2Cu202 is a two-dimensional superconductor. 

Several structural features, including electron transfer between atoms of different electronegativity, oxygen deficiency, and unsynchronized resonance of valence bonds, as well as tight binding of atoms and the presence of both hypoelectronic and hyperelectronic elements, cooperate to confer metallic properties and high-temperature superconductivity on compounds such as (Sr.Ba.Y.LahCuO,-,. 

The discovery of high-temperature superconductivity in mixed oxides, such as the lanthanum-barium-copper oxide complexes, has created a great deal of interest in these materials. Superconductivity, that is, the absence of any resistance to the flow of electric current, is now possible at temperatures above the temperature of liquid nitrogen (77K). Many problems remain in the development of practical processes for these materials and commercialization is not likely to occur until these problems are solved. Among the several processing techniques now used, CVD appears one of the most successful. 

National Academy of Sciences-National Academy of Engineering-Institute of Medicine, Committee on Science, Engineering, and Public Policy. "Research Briefing on High-Temperature Superconductivity," in Research Briefings 1987. Washington, D.C. National Academy Press, 1987. 

Tacliibana, A. Density functional theory for hidden high-/, superconductivity. In High Temperature Superconducting Materials, Hatfield W.E. and Miller, Jr., J.H. (Eds.), Dekker, New York. 

An NMR setup based on a high-temperature superconducting materials... 

Figure 16 shows an NMR system based on the bulk high-temperature superconducting magnet and the OPENCORE NMR spectrometer, in which 1H NMR in water was performed in 4.7 T. 

Figure 16 An NMR system using a bulk high-temperature superconducting magnet and the OPENCORE NMR spectrometer. The temperature of the bulk SCM was 40 K, while the sample space with a diameter of 24 mm was at room temperature. On the computer screen displayed is a hi FID of water taken on this system. The resonance frequency was 200.045 MHz.

Invent materials with useful electrical and optical properties, including high-temperature superconductivity. 

Brooks JS (2007) In Schrieffer JR, Brooks JS (eds) Handbook of high-temperature superconductivity. Springer, Berlin Heidelberg New York, p 463... 

Although the high-temperature superconducting phases are formed from insulating materials by the introduction of defects, the precise relationship between dopant, structure, and properties is not fully understood yet. For example, in most of the cuprate phases it is extremely difficult to be exactly sure of the charges on the individual ions, and because of this the real defect structures are still uncertain. 

High temperature strength, 13 470 High temperature superconducting ceramic, 23 836-851... 

High-temperature superconducting power cable system, 23 854... 

The compound consisting of yttrium, copper, and barium oxide, commonly called compound 1-2-3, was formed in 1987 by research scientists at the universities of Alabama and Houston. It had limited superconducting capabilities. It has been known for some time that conductors of electricity such as copper resist, to some extent, the flow of electrons at normal temperatures, but at temperatures near absolute zero (zero Kelvin = -273°C), this resistance to the flow of electrons in some materials is reduced or eliminated. The 1-2-3 compound proved to be superconducting at just 93°K, which is still much too cold to be used for everyday transmission of electricity at normal temperatures. Research continues to explore compounds that may achieve the goal of high-temperature superconductivity. 

Burns, G. (1993). In High-Temperature Superconductivity. Boston Academic Press. Burton, W. K., Cabrera, N. and Frank, F. C. (1951). Philos. Trans. R. Soc. London A243, 299-358. 

Chu CW (2009) High-temperature superconductivity alive and kicking. Nat Phys 5 787-789... 

In 1988, Cava and co-workers also prepared (88a) a quaternary oxide, Ba/K/Bi/O, and observed superconductivity at -28 K. This compound was the first "non-transition metal" oxide with a Tc above the legendary "alloy record" of 23 K. Further studies indicated (88a) that the optimum composition for "high temperature" superconductivity in this system was Ba0 6K0 4BiO3 x, having a Tc of 30.5 K (Figure 17). The samples were multiphase, and the superconducting fraction varied from 3 to 25%. Superconductivity for the rubidium-substituted compound was observed at -28.6 K. 

Alkaline-earth substitution in LajCuC was also investigated (121)(128)(131) during the early 1970 s in the U.S.S.R., India, and Japan, but unfortunately, these materials were never investigated at sufficiently low temperatures for detection of their superconducting properties. This oversight resulted in a 16 year delay in the discovery of high temperature superconductivity in copper-oxide compounds. 

In the system Ba(Pb1.xBix)Os, the compound with x = 0.25 must be considered the first discovered ceramic material showing high-temperature superconductivity (7). Structure determinations have been carried out over the entire range of composition (8)-(ll) and the refined parameters are presented in Table 2. Superconductivity in this system exists only for values of x between 0.05 and 0.35. The value of the critical temperature increases with x, reaches a maximum value Tc 13K for x = 0.25, and then decreases. For x > 0.35, the material becomes a semiconductor. 

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