Bulk High-Temperature Superconductors: Simulation of Electromagnetic Properties

Important Considerations for Processing Bi-Based High-Temperature Superconducting Tapes and Films for Bulk Applications

MRS Bulletin ◽

10.1557/s0883769400041853 ◽

1992 ◽

Vol 17 (8) ◽

pp. 45-51 ◽

Cited By ~ 28

Author(s):

Eric E. Hellstrom

Keyword(s):

High Temperature ◽

Magnetic Fields ◽

Materials Science ◽

Weak Link ◽

High Temperature Superconductors ◽

Electromagnetic Properties ◽

High Magnetic Fields ◽

Large Current ◽

Current Densities ◽

Made In

High-temperature superconductors are brittle oxide ceramics, yet they have been made into wire that has been wrapped into solenoids and used in demonstration magnets and motors. Fabricating wires from these ceramics is an extremely challenging materials science process that requires a precisely engineered microstructure with the correct chemical, mechanical, and electromagnetic properties if these wires are to transport large current densities (Jc) in high magnetic fields. Heine et al. first demonstrated that wires of these materials could carry high Jc in very high magnetic fields. At 4.2 K, the oxide superconducting wires can carry higher Jc at higher magnetic fields than conventional Nb-Ti or Nb3Sn wires (Figure 1), and as shown in the companion article in this issue by Kato et al. they can also have high Jc at 77 K.Of the three major families of high-temperature superconductors, YBa2Cu3O7-x, Bi-Sr-Ca-Cu-O (BSCCO), and Tl-Ba-Ca-Cu-O, the best wires to date have been made in the BSCCO system. At present, all YBa2Cu3O7-x wires are weak linked and have only small Jc in magnetic fields. In the Tl-based system, the superconducting properties are potentially very interesting, but the toxicity of Tl and the system's complex processing have limited conductor development. For the Bi-based system, the basic processing steps are becoming known, the grains are well connected, and the weak link problem can be controlled. This permits applications in the temperature range 4–77 K, depending on the field and current density requirements of the particular use.

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Theoretical Study of THz Emission from HTS Cuprate

10.1093/oxfordhb/9780198738169.013.9 ◽

2017 ◽

Author(s):

H. Asai

Keyword(s):

High Temperature ◽

Josephson Junctions ◽

Cuprate Superconductors ◽

High Temperature Superconductors ◽

Electromagnetic Properties ◽

Effect Of Temperature ◽

Temperature Inhomogeneity ◽

High Anisotropy ◽

Strong Excitation ◽

Almost All

This article examines the THz emission from high-temperature superconducting (HTS) cuprates in the mesoscopic state using the intrinsic Josephson junction model. Cuprate superconductors are high-temperature superconductors that exhibit exotic electromagnetic properties. One of the remarkable features of HTS cuprates is high anisotropy due to their layered structures. Almost all HTS cuprates are composed of stacks of CuO2 layers and blocking layers which supply charge carriers to the CuO2 layers. The crystal structures of the HTS cuprates naturally form Josephson junctions known as intrinsic Josephson junctions (IJJs). This article first describes the basic theory of IJJ and the mechanism of THz emission before discussing the effect of temperature inhomogeneity on the emission properties. It then introduces a novel IJJ-based THz emitter that utilizes laser heating. Theoretical results show that the THz emission is caused by the strong excitation of transverse Josephson plasma waves in IJJs under a direct current bias.

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