A New Generation of In Situ Mg2 Wires With Improved Jc and Birr Values Obtained by Cold Densification (CHPD)

Flukiger, René-Louis; Hossain, Md Shahriar Al; Senatore, Carmine; Buta, Florin; Rindfleisch, Matt

doi:10.1109/TASC.2010.2101571

Scientific article

English

A New Generation of In Situ Mg₂ Wires With Improved J_c and B_irr Values Obtained by Cold Densification (CHPD)

Contributors

Flukiger, René-Louis; Hossain, Md Shahriar Al; Senatore, Carmine

; Buta, Florin; Rindfleisch, Matt

Published in

IEEE transactions on applied superconductivity, vol. 21, no. 3, p. 2649-2654

Publication date

2011

Abstract

By means of Cold High Pressure Densification (CHPD), the critical current density, Jc, of binary and alloyed MgB2 wires has been enhanced by more than a factor 2 at 4.2 K and at fields up to 19 T. The relative MgB2 mass density of binary MgB2 wires was enhanced to ~ 54% after applying 2.5 GPa at 300 K before reaction. In C4H6O5 (malic acid) alloyed wires, densification also caused the enhancement of Birr, as a consequence of a slightly enhanced C content, determined by X ray diffraction. Almost isotropic Jc values were obtained for C4H6O5 added wires of 1 × 0.6 mm2 cross section, the values of Jc(4.2 K)=1 × 104 A/cm2 for parallel and perpendicular fields being obtained at 13.8 and 13.4 T, respectively (1 μV/cm criterion). The corresponding values for 20 K were both close to 6.2 T. The value of Birr// at 20 K was 11 T. The positive effects of cold densification on Jc and Birr on MgB2 was also observed on 150 mm long wires alloyed with C4H6O5 (malic acid) or with SiC, by the succession of 6 overlapping pressure steps. This process can be extended to long wire lengths: by means of a newly developed prototype machine with an automatic press/release/advance sequence, a first wire length of 1 m was densified at 1.5 GPa, yielding Jc(4.2 K) = 1 x 104 A/cm2 at 13.1 T. Further improvements are expected after optimization

Keywords

Cold densification
Critical current density
Electrical resistivity
MgB2
Upper critical field.

UNIGE affiliation entities

UNIGE research groups

Groupe Senatore

Citation (ISO format)

FLUKIGER, René-Louis et al. A New Generation of In Situ Mg₂ Wires With Improved J_c and B_irr Values Obtained by Cold Densification (CHPD). In: IEEE transactions on applied superconductivity, 2011, vol. 21, n° 3, p. 2649–2654. doi: 10.1109/TASC.2010.2101571

Article (Published version)

Identifiers

PID : unige:36281
DOI : 10.1109/TASC.2010.2101571

Additional URL for this publication

http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=5704210

Journal ISSN

1051-8223

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