Large upper critical field and irreversibility field in MgB2 wires with SiC additions

• Published in: Applied physics letters 2005-02, Vol.86 (9)
• Main Authors: Sumption, M. D., Bhatia, M., Rindfleisch, M., Tomsic, M., Soltanian, S., Dou, S. X., Collings, E. W.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.1872210

Resistive transition measurements are reported for MgB2 strands with SiC dopants. The starting Mg powders were 325 mesh 99.9% pure, and the B powders were amorphous, 99.9% pure, and at a typical size of 1–2 μm. The SiC was added as 10 mol % of SiC to 90 mol % of binary MgB2 [(MgB2)0.9(SiC)0.1]. Three different SiC powders were used; the average particle sizes were 200 nm, 30 nm, and 15 nm. The strands were heat treated for times ranging from 5 to 30 min at temperatures from 675 °C to 900 °C. Strands with 200 nm size SiC additions had μ0Hirr and Bc2 which maximized at 25.4 T and 29.7 T after heating at 800 °C for 30 min. The highest values were seen for a strand with 15 nm SiC heated at 725 °C for 30 min which had a μ0Hirr of 29 T and a Bc2 higher than 33 T.