Large transport critical currents in unsintered MgB2 superconducting tapes

Grasso, G.; Malagoli, Andrea; Ferdeghini, C.; Roncallo, S.; Braccini, V.; Siri, A. S.; Cimberle, M. R.

doi:10.1063/1.1384905

Cited by 346 publications

(224 citation statements)

References 9 publications

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“…The first attempt at wire fabrication was the magnesium vapor diffusion to boron fibers presented by Canfield et al 2 . Recent efforts at wire fabrication have centered on developing the powder-in-tube (PIT) process due to its greater easiness of scaled up production [3][4][5][6][7] . The transport critical current density J c at 4.2K and in self-field of the PIT processed tapes has already exceeded the practical level of 10 5 A/cm 2 .…”

Section: (Received Date)mentioning

confidence: 99%

Approach for the fabrication of MgB2 superconducting tape with large in-field transport critical current density

Komori

Kawagishi

Takano

et al. 2002

Applied Physics Letters

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The paper reports the first successful fabrication of MgB 2 superconducting tape using a flexible metallic substrate as well as its strong pinning force, which was verified by direct measurement of transport critical current density. The tape was prepared by depositing MgB 2 film on a Hastelloy tape buffered with an YSZ layer. The J c of the tape exceeds 10 5 A/cm 2 at 4.2K and 10T, which is considered as a common benchmark for magnet application. The J c dependence on magnetic field remains surprisingly very small up to 10T, suggesting that the tape has much better magnetic field characteristic than conventional Nb-Ti wires in liquid helium.The newly discovered MgB 2 superconductor 1 is expected to be useful for various electric power applications as well as electronic device applications because its transition temperature is much higher than those of conventional metallic superconductors such as Nb-Ti and Nb 3 Sn. In order to evaluate the potentiality for p ower applications, the development of wire processing techniques is essential. The first attempt at wire fabrication was the magnesium vapor diffusion to boron fibers presented by Canfield et al 2 . Recent efforts at wire fabrication have centered on developing the powder-in-tube (PIT) process due to its greater easiness of scaled up production [3][4][5][6][7] . The transport critical current density J c at 4.2K and in self-field of the PIT processed tapes has already exceeded the practical level of 10 5 A/cm 2 . However, the J c rapidly decreases in an applied magnetic field due to its weak pinning force. The J c values at 4.2K and 10T reported so far for PIT processed wires and tapes remain as low as the order of 10 3 A/cm 2 , although the values are being steadily improved.In contrast to the relatively poor in-field J c values of the tapes and bulks, there are several papers on MgB 2 thin films, which reported very much higher Hc 2 values and J c values in applied magnetic fields than those of tape and bulk samples 8,9 . Kim et al 9 reported a large transport J c value of 10 5 A/cm 2 at 5T and 15K for the c-axis oriented MgB 2 film prepared on an Al 2 O 3 substrate. Those results suggest to us that the MgB 2 phase formed by vapor deposition techniques has extremely strong pinning force. However, all experiments on the thin films have been performed using ceramic substrates, which are not suitable for long length production of flexible conductor. This paper reports a successful new approach to fabricate MgB 2 tape that is the combination of the high critical current density achieved by vapor deposition and the use of flexible metallic substrate tape. The technique is similar to the so-called coated conductor techniques developed for YBa 2 Cu 3 O y (Y-123), where Y-123 thin films are deposited on various buffer layers on a metallic substrate 10 -12 . The MgB 2 tape obtained in this work has an excellent transport J c of 1.1x10 5 A/cm 2 at 4.2.K and 10T. It is also surprising that the J c dependence on the magnetic field remains extremely small up to 10T, ...

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Section: (Received Date)mentioning

confidence: 99%

Approach for the fabrication of MgB2 superconducting tape with large in-field transport critical current density

Komori

Kawagishi

Takano

et al. 2002

Applied Physics Letters

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“…Due to its intermediate transition temperature, weak-link free grain boundaries [5] and low material cost, this material is interesting for potential applications such as MRI (magnetic resonance imaging) and transformers at operating temperature of 20-30K. Soon after its discovery, several research groups have tried to demonstrate the feasibility of fabrication of MgB 2 wires or tapes with high critical current density using the Powder-In-Tube (PIT) method [6][7][8][9][10][11]. Large critical current densities of 10 6 A/cm 2 and significant enhancement of irreversibility line and H c2 have been reported in MgB 2 films grown on single-crystalline substrates [12][13].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and transport critical currents of multifilamentary MgB2/Fe wires and tapes

Suo¹,

Beneduce²,

Su³

et al. 2002

Supercond. Sci. Technol.

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Multifilamentary MgB 2 /Fe wires and tapes with high transport critical current densities have been fabricated using a straightforward powder-in-tube (PIT) process.After annealing, we measured transport j c values up to 1.1 × 10 5 A/cm 2 at 4.2 K and in a field of 2 T in a MgB 2 /Fe square wire with 7 filaments fabricated by two-axial rolling, and up to 5 × 10 4 A/cm 2 at 4.2 K in 1 T in a MgB 2 /Fe tape with 7 filaments. For higher currents these multifilamentary wires and tapes quenched due to insufficient thermal stability of filaments. Both the processing routes and deformation methods were found to be important factors for fabricating multifilamentary MgB 2 wires and tapes with high transport j c values.

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“…Some mechanical properties of the MgB 2 PIT wires have been reported in the literature, with particular emphasis to the effect of the thermal treatment. Some attempt to make industrial-like magnets by the "react-and-wind" process using MgB 2 PIT wires has been also performed [1,2], even if the wires performances, in term of critical currents, were not optimal. An alternative process to the MgB 2 PIT manufacturing is represented by the Liquid Mg Reactive Infiltration (Mg-RLI) process [3], which leads to special hollow wires.…”

Section: Introductionmentioning

confidence: 99%

MECHANICAL PROPERTIES OF MgB[sub 2] HOLLOW WIRES

Saglietti¹,

Perini²,

Albisetti³

et al. 2010

AIP Conference Proceedings

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The peculiar morphology of the MgB 2 wires resulting from the reactive liquid Mg infiltration technology (Mg-RLI), characterized by an annular distribution of the superconducting material, originates a peculiar mechanical behaviour. Monofilament wires of different size and different thickness of the superconducting material have been subjected to tensile and flexural deformation, in order to gain a comprehensive description of the mechanical behaviour of the superconducting material. A model based on a simplified description of the mechanical behaviour in term of few parameters aids the interpretation of the various experimental measurements and represents a tool to evaluate the mechanical behaviour of different specifically sized wires. Other variables entering in the mechanical model take into account the filling of the internal hole with the metallic Mg and the strength of the external metallic sheath. The present mechanical analysis gives hints on the limits of applicability of the react-and-wind process in magnet manufacturing with this kind of wires. A further output of the study is to find the variation of the intrinsic mechanical properties of the MgB 2 material as a function of the Carbon doping, obtained via SiC doping.

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Large transport critical currents in unsintered MgB2 superconducting tapes

Cited by 346 publications

References 9 publications

Approach for the fabrication of MgB2 superconducting tape with large in-field transport critical current density

Approach for the fabrication of MgB2 superconducting tape with large in-field transport critical current density

Fabrication and transport critical currents of multifilamentary MgB2/Fe wires and tapes

MECHANICAL PROPERTIES OF MgB[sub 2] HOLLOW WIRES

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