Role of carbon in enhancing the performance of MgB2 superconductor

✍ Scribed by V.P.S. Awana; Arpita Vajpayee; Monika Mudgel; Rajeev Rawat; Somobrata Acharya; H. Kishan; E. Takayama-Muromachi; A.V. Narlikar; I. Felner

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 388 KB
• Volume: 467
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2007.08.011

✦ Synopsis

The enhancement of the critical current density (J c (H)) of carbon and nano-SiC doped MgB 2 is presented and compared. The upper critical field (H c2 ) being determined from resistivity under magnetic field experiments is though improved for both C substitution and nano-SiC addition the same is more pronounced for the former. In MgB 2Àx C x carbon is substituted for boron that induces disorder in the boron network and acts as internal pinning centres. The optimal J c (H) values are obtained for x = 0.1 sample. In case of nano-SiC doped in MgB 2 , the J c (H) improves more profoundly and two simultaneous mechanisms seems responsible to this enhancement. Highly reactive nano-SiC releases free carbon atom, which gets easily incorporated into the MgB 2 lattice to act as intrinsic pinning centres. Further enhancement is observed for higher nano-SiC concentrations, where the un-reacted components serve as additional extrinsic pinning centres.