(RE)Ba2Cu3O7 Coated Conductors for AC and DC Applications

J. Phys.: Condens. Matter

Majoroš

2009

Magnetic materials can help to improve the performance of practical superconductors on the macroscale/microscale as magnetic diverters and also on the nanoscale as effective pinning centres. It has been established by numerical modelling that magnetic shielding of the filaments reduces AC losses in self-field conditions due to decoupling of the filaments and, at the same time, it increases the critical current of the composite. This effect is especially beneficial for coated conductors, in which the anisotropic properties of the superconductor are amplified by the conductor architecture. However, ferromagnetic coatings are often chemically incompatible with YBa(2)Cu(3)O(7) and (Pb,Bi)(2)Sr(2)Ca(2)Cu(3)O(9) conductors, and buffer layers have to be used. In contrast, in MgB(2) conductors an iron matrix may remain in direct contact with the superconducting core. The application of superconducting-magnetic heterostructures requires consideration of the thermal and electromagnetic stability of the superconducting materials used. On one hand, magnetic materials reduce the critical current gradient across the individual filaments but, on the other hand, they often reduce the thermal conductivity between the superconducting core and the cryogen, which may cause destruction of the conductor in the event of thermal instability. A possible nanoscale method of improving the critical current density of superconducting conductors is the introduction of sub-micron magnetic pinning centres. However, the volumetric density and chemical compatibility of magnetic inclusions has to be controlled to avoid suppression of the superconducting properties.

Section: Architecture Of the Coated Conductors On Ferromagnetic Subst...mentioning

confidence: 99%

Section: Architecture Of the Coated Conductors On Ferromagnetic Subst...mentioning

confidence: 99%

Superconducting–magnetic heterostructures: a method of decreasing AC losses and improving critical current density in multifilamentary conductors

J. Phys.: Condens. Matter

Majoroš

2009

“…So we can imagine the use of a coated conductor tape with a ferromagnetic substrate inside (in the inner layer) and outside (in the outer layer) of the cable so that the substrates could not see any magnetic field. The minimum layer separation is determined by the thickness of the insulation, which depends on the voltage level used [46]. This cable architecture was originally developed in Brookhaven National Laboratories some decades ago using Nb 3 Sn tapes, see, e.g., [46].…”

Section: Architecture Of the Coated Conductors On Ferromagnetic Subst...mentioning

confidence: 99%

“…The minimum layer separation is determined by the thickness of the insulation, which depends on the voltage level used [46]. This cable architecture was originally developed in Brookhaven National Laboratories some decades ago using Nb 3 Sn tapes, see, e.g., [46].…”

Section: Architecture Of the Coated Conductors On Ferromagnetic Subst...mentioning

confidence: 99%

“…To demonstrate the feasibility of producing YBa 2 Cu 3 O 7coated conductors with a low-cost ferromagnetic substrate, we first deposited YBCO by PLD on NiFe buffered with Y 2 O 3 or CeO 2 [46,47]. Well-textured buffer layers on YBCO were obtained and a critical temperature T c ≈ 87 K measured (figure 6(a)).…”

Section: Monofilamentary Ybco-coated Conductors On Nife Substratesmentioning

confidence: 99%

See 1 more Smart Citation

Influence of magnetic materials on the transport properties of superconducting composite conductors

Supercond. Sci. Technol.

Majoroš

Campbell

et al. 2009

Magnetic materials can help to improve the performance of practical superconductors on the macro/microscale as magnetic diverters and also on the nanoscale as effective pinning centres. It has been established by numerical modelling that magnetic shielding of the filaments reduces ac losses in self-field conditions due to decoupling of the filaments and, at the same time, it increases the critical current of the composite. This effect is especially beneficial for coated conductors, in which the anisotropic properties of the superconductor are amplified by the conductor architecture. However, ferromagnetic coatings are often chemically incompatible with YBa 2 Cu 3 O 7 and (Pb, Bi) 2 Sr 2 Ca 2 Cu 3 O 9 conductors, and buffer layers have to be used. In contrast, in MgB 2 conductors an iron matrix may remain in direct contact with the superconducting core. The application of superconducting-magnetic heterostructures requires consideration of the thermal and electromagnetic stability of the superconducting materials used. On the one hand, magnetic components reduce the critical current gradient across the individual filaments but, on the other hand, they often reduce the thermal conductivity between the superconducting core and the cryogen, which may cause the destruction of the conductor in the event of thermal instability. A possible nanoscale method of improving the critical current density of superconducting conductors is the introduction of sub-micron magnetic pinning centres. However, the volumetric density and chemical compatibility of magnetic inclusions has to be controlled to avoid suppression of the superconducting properties.

Superconductivity and Superconductors

Kirk-Othmer Encyclopedia of Chemical Technology

2005

This article aims to address the issue of superconductivity and superconductors from the point of view of technology and applications, despite the fact that the majority of recent developments relate more to the fundamental aspects of superconductivity. The technology sections focus on the discovery of superconductivity and the phenomena and characteristics that define it. Low temperature superconductors (LTS) are discussed. Niobium and tantalum devices fall into this category. These materials are probably the most important electrode material for tunnel junction fabrication and are used in superconducting devices, eg, the superconducting quantum interference device (SQUID), X‐ray detectors, optical detectors, and mixers. Magnesium dibromide has made us aware of the possibility of the existence of new superconducting materials and this compound is detailed. High temperature ceramic superconductors are discussed and they focus mainly on the evolution of superconductivity by chemical doping of copper and its compounds. An extensive section on application includes details on the following uses: in transmission cables, research electromagnets, electromagnets for nmr and mri systems, current leads, fault current limiters, magnetically guided surgical instruments, and levitating train, to name a few.