Superconductivity of bulk MgB2 + nano(n)-SiC composite system: A high field magnetization study

Abstract

We study the effect of nano(n)-SiC addition on the crystal structure, critical temperature (Tc), critical current density (Jc) and flux pinning in MgB2 superconductor. X-ray diffraction patterns show that all the samples have MgB2 as the main phase with very small amount of MgO, further with n-SiC addition the presence of Mg2Si is also noted and confirmed by SEM & EDS. The Tc value for the pure MgB2 is 18.9K under 8 Tesla applied field, while is 20.8K for the 10-wt % n-SiC doped sample under the same field. This points towards the increment in upper-critical field value with n-SiC addition. The irreversibility field (Hirr) for the 5% n-SiC added sample reached 11.3, 10 and 5.8 Tesla, compared to 7.5, 6.5, and 4.2 Tesla for the pure MgB2 at 5, 10 and 20K respectively. The critical current density (Jc) for the 5-wt % n-SiC added sample is increased by a factor of 35 at 10K and 6.5 Tesla field and by a factor 20 at 20K and 4.2 Tesla field. These results are understood on the basis of superconducting condensate (sigma band) disorder and ensuing intrinsic pining due to B site C substitution clubbed with further external pinning due to available n-SiC/Mg2Si pins in the composite system.

arXiv comment19 pages of Text + Figs. comments/suggestions are welcome ([email protected])

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• Physical Property Characterization of Bulk MgB2 Superconductor
• Superconducting Properties of adipic acid doped Bulk MgB2 Superconductor
• Effect of synthesis temperature on superconducting properties of n-SiC added bulk MgB2 superconductor
• Synthesis and Characterization of Excess Magnesium MgB2 Superconductor under Inert Carbon Environment
• Reaction method control of impurity scattering in C-doped MgB2, proving the role of defects besides C substitution level
• Superconducting performance of ex-situ SiC-doped MgB2 mono-filamentary tapes