Superconductivity transport

Clearly, since the Cu02 planes, which play an essential role in the superconducting transport, are disrupted across the (010)(001) boundaries, they are expected to show weak-link behavior. However, since the Cu02 planes are continuous across (013)(013) boundaries, the latter may provide good supercurrent conducting paths across the 90° [100] tilt grain boundaries, resulting possibly in weak-link free behavior [10.43]. Measurements across individual... 

Metals and semiconductors are electronic conductors in which an electric current is carried by delocalized electrons. A metallic conductor is an electronic conductor in which the electrical conductivity decreases as the temperature is raised. A semiconductor is an electronic conductor in which the electrical conductivity increases as the temperature is raised. In most cases, a metallic conductor has a much higher electrical conductivity than a semiconductor, but it is the temperature dependence of the conductivity that distinguishes the two types of conductors. An insulator does not conduct electricity. A superconductor is a solid that has zero resistance to an electric current. Some metals become superconductors at very low temperatures, at about 20 K or less, and some compounds also show superconductivity (see Box 5.2). High-temperature superconductors have enormous technological potential because they offer the prospect of more efficient power transmission and the generation of high magnetic fields for use in transport systems (Fig. 3.42). 

The importance of materials science to U.S. competitiveness can hardly be overstated. Key materials science areas underlie virtually every facet of modem life. Semiconductors underpin our electronics industry. Optical fibers are essential for communications. Superconducting materials will probably affect many areas ceramics, composites, and thin films are having a big impact now in transportation, construction, manufacturing, and even in sports—tennis rackets are an example. 

Besides the crust and the hadron shell, the hybrid star contains also a quark core. Both the nucleon shell and the quark core can be in superconducting phases, in dependence on the value of the temperature. Fluctuations affect transport coefficients, specific heat, emissivity, masses of low-lying excitations and respectively electromagnetic properties of the star, like electroconductivity and magnetic field structure, e.g., renormalizing critical values of the magnetic field (/ ,, Hc, Hc2). 

Auban-Senzier P, Pasquier C, Jerome D, Carcel C, Fabre JM (2003) From Mott insulator to superconductivity in (TMTTF)2BF4 high pressure transport measurements. Synth Met 133-134 11-14... 

Tajima N, Ebina-Tajima A, Tamura M, Nishio Y, Kajita K (2002) Effects of uniaxial strain on transport properties of organic conductor a-(BEDT-TTF)2l3 and discovery of superconductivity. J Phys Soc Jpn 71 1832-1835... 

A comprehensive report which focussed on the La2 xSrxCu O4-x/2+S ser es was published (139) in 1983 by this research group. In this broad review they reported the magnetic and electrical transport properties of these mixed-valent copper oxides in the temperature range 120-650 K. They concluded that the original semiconducting behavior in La2Cu04 transformed to semi-metallic behavior as the Cu3+ content increased with Sr-substitution. No experiments were conducted below 50 K, and therefore superconductivity was not observed. Three series of compounds, with 0.00 < x < 1.20 were... 

A substitution for Cu by Fe, Co or Mn in the Bi2Sr2CuOy phase produces a drastic change in the transport properties, in particular an electronic transition from superconducting to semiconducting for Fe or Co or to insulating for Mn. This indicates that the presence of 3d metal oxygen layers is not, by itself, sufficient for... 

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