High temperature superconductors HTS

Abstract An Eddy current method applying a High Temperature Superconductor ( HTS ) DC SQUID sensor operating at Uquid nitrogen temperature (77K) is presented. The method is developed for the detection of surface or surface near defects. We compare the performance of the SQUID system with the performance gained from a commercial Eddy current system, while using identical probes. The experimental data are obtained on defects in gas turbine blades. The advantage of planar conformable probes for the use with the SQUID is discussed. 

Superconductivity The physical state in which all resistance to the flow of direct-current electricity disappears is defined as superconductivity. The Bardeen-Cooper-Schriefer (BCS) theoiy has been reasonably successful in accounting for most of the basic features observed of the superconducting state for low-temperature superconductors (LTS) operating below 23 K. The advent of the ceramic high-temperature superconductors (HTS) by Bednorz and Miller (Z. Phys. B64, 189, 1989) has called for modifications to existing theories which have not been finahzed to date. The massive interest in the new superconductors that can be cooled with liquid nitrogen is just now beginning to make its way into new applications. 

Electrodeposition was used to prepare a biaxially textured Gd2Zr207 (GZO) buffer layer on Ni-W substrates.129 Buffer layers provide chemically inert, continuous, and smooth bases for the growth of the superconductor oxide films. They also prevent both the diffusion of metal to the high-temperature superconductor (HTS) layer and the oxidation of the metal substrate when superconductor oxide films are processed at high temperature (-800 °C) in an oxygen atmosphere (100ppm or more). 

High temperature superconductors (HTS), 23 814, 826, 829. See also Anisotropic HTS HTS entries applications of, 23 852-872 layered, 23 827, 840 magnetic phase diagram of, 23 838-842 p- and n-type, 23 838 structural anisotropy and fluxon line fragmentation in, 23 841 thallium- and mercury-based, 23 848-850... 

See also Josephson entries HTS materials, 23 819, 839. See also High temperature superconductors (HTS) HTS superconducting current leads, 23 855 HTS tapes, 23 854... 

High Temperature Superconductor (HTS) materials are wound within a cable system designed to also contain liquid nitrogen coolant. 

Type 11 superconductors are normally limited by the Ginzburg-Landau ratio k = X/ > l/ /l. One special attribute of a high-temperature superconductor (HTS) materials is its small coherence length in comparison with a low-temperature superconductor (LTS), and its anisotropy due to the two-dimensional (2-D) character of the layered crystal structures. The coherence length is on the order of unit cell dimensions, where For example, yttrium barium copper oxide (YBCO)... 

Bardeen-Cooper-Schrieffer (BCS) Theory 526 High-Temperature Superconductor (HTS) Cuprates (Unconventional Superconductors) 528 Heavy Fermion Superconductors 533 Type II Superconductors 534 References 535... 

Figure 2.32. Photograph of a high-temperature superconductor (HTS) wire used for electrical power applications. LN refers to the flow direction of the liquid nitrogen cryogenic cooling fluid. Photograph courtesy of Southwire Company (http //www.southwire.com).

Magnesia, MgO, not commonly used as a substrate material because its high sintering temperatures result in low-density ceramics. Some more recent cryogenic applications as substrates for superconductor substrates have emerged as a result of its thermal expansion match to high-temperature superconductor (HTS) materials. 

High-temperature superconductors HTS for electric energy transport. 

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