Progress in Critical Current Density (J{sub c}) in Sintered MgB{sub 2} Bulks

Journal Article · Sat Sep 15 04:00:00 EDT 2018 · Journal of Superconductivity and Novel Magnetism

DOI:https://doi.org/10.1007/S10948-018-4777-6· OSTI ID:22773790

Murakami, M. ^[1]

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1. Shibaura Institute of Technology, Superconducting Materials Laboratory, Graduate School of Science and Engineering (Japan)

The present paper focuses on methods of further improving the flux pinning and critical current density of disk-shaped MgB{sub 2} bulk superconductors by adding excess Mg metal in combination with an optimum silver content and optimized processing conditions. Bulk MgB{sub 2} samples were produced by in situ solid-state reaction in Ar gas ambient using high purity commercial powders of Mg metal and 1.5 wt% carbon-coated amorphous B powders mixed in a fixed ratio of Mg/B = 1.1:2. Further, 4 wt% silver was added to improve flux pinning as well as mechanical performance of the bulk MgB{sub 2} material. The magnetization measurements confirmed a sharp superconducting transition with T{sub c,onset} at around 37 K, which is only by 1 K lower than in bulk MgB{sub 2} material produced without carbon-coated amorphous boron. The critical current density (J{sub c}) values significantly improved in the MgB{sub 2} material with 4 wt% of silver and 1.5 wt% of carbon-coated amorphous boron, sintered at 775 {sup ∘}C for 3 h. At 20 K, this sample showed J{sub c} at around 500 and 350 kA/cm{sup 2} in the self-field and 1 T, respectively, which makes it suitable for several industrial applications.

• OSTI ID: 22773790
• Journal Information: Journal of Superconductivity and Novel Magnetism, Journal Name: Journal of Superconductivity and Novel Magnetism Journal Issue: 9 Vol. 31; ISSN 1557-1939
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BORON
CARBON
CRITICAL CURRENT
MAGNESIUM
MAGNESIUM BORIDES
MAGNETIC FLUX
MAGNETIZATION
POWDERS
SILVER
SINTERING
SUPERCONDUCTORS