Enhancement of the critical current density and flux pinning of MgB2 superconductor by nanoparticle SiC doping

TL;DR

Nano-SiC doping significantly enhances the flux pinning and critical current density of MgB2 superconductors with minimal Tc reduction, making them more viable for high-field applications.

Contribution

This study demonstrates that nano-SiC doping improves MgB2's flux pinning and Jc, with co-substitution of Si and C balancing Tc reduction and significantly boosting performance.

Findings

Jc increased by factors of 32, 42, and 14 at various temperatures and fields.

Doped MgB2's Jc at 20K and 2T is comparable to top-tier tapes.

Doped MgB2 exhibits superior Jc compared to thin films and tapes.

Abstract

Doping of MgB2 by nano-SiC and its potential for improvement of flux pinning was studied for MgB2-x(SiC)x/2 with x = 0, 0.2 and 0.3 and a 10wt% nano-SiC doped MgB2 samples. Co-substitution of B by Si and C counterbalanced the effects of single-element doping, decreasing Tc by only 1.5K, introducing pinning centres effective at high fields and temperatures and enhancing Jc and Hirr significantly. Compared to the non-doped sample, Jc for the 10wt% doped sample increased by a factor of 32 at 5K and 8T, 42 at 20K and 5T, and 14 at 30K and 2T. At 20K, which is considered to be a benchmark operating temperature for MgB2, the best Jc for the doped sample was 2.4x10^5A/cm2 at 2T, which is comparable to Jc of the best Ag/Bi-2223 tapes. At 20K and 4T, Jc was 36,000A/cm2, which was twice as high as for the best MgB2 thin films and an order of magnitude higher than for the best Fe/MgB2 tapes. Because of such high performance, it is anticipated that the future MgB2 conductors will be made using the formula of MgBxSiyCz instead of the pure MgB2.