Flux pinning mechanism in SiC and nano-C doped MgB2: Evidence for transformation from δTc to δℓ pinning

Authors

Shaban Reza Ghorbani, Hakim Sabzevari University, University of WollongongFollow
G Farshidnia, Hakim Sabzevari University
Xiaolin Wang, University of WollongongFollow
S X. Dou, University of WollongongFollow

RIS ID

96258

Publication Details

Ghorbani, S. R., Farshidnia, G., Wang, X. L. & Dou, S. X. (2014). Flux pinning mechanism in SiC and nano-C doped MgB₂: Evidence for transformation from δT_c to δℓ pinning. Superconductor Science and Technology, 27 (12), 1-7.

Abstract

Magnetic and transport properties of 10 wt% SiC doped MgB₂ and 5 wt% nano-C doped MgB₂ were studied by resistance and critical current density measurements. The results showed improvement of the critical current density for the MgB₂ superconductor doped with SiC in comparison with the nano-C doped sample. The flux pinning mechanisms of both doped MgB₂ superconductors have been investigated based on the collective theory. It was found that the pinning mechanism in MgB₂ was transformed by SiC doping from transition temperature fluctuation induced pinning, δT_c pinning, to mean free path fluctuation induced pinning, δℓ pinning, while in the MgB₂ doped with nano-C, δT_c and δℓ pinning coexist. Their contributions are strongly temperature dependent, however. The δℓ pinning is dominant at low temperature, decreases with increasing temperature, and is suppressed completely at temperatures close to T_c. The δT_c pinning mechanism shows the opposite trend.