Hollow carbon spheres as an efficient dopant for enhancing critical current density of MgB2 based tapes

TL;DR

This study demonstrates that hollow carbon spheres significantly improve the critical current density and irreversibility field of MgB2 superconducting tapes, outperforming some traditional dopants at high magnetic fields.

Contribution

The paper introduces hollow carbon spheres as a novel dopant that enhances MgB2 tape performance more effectively than nano-SiC and other carbon sources.

Findings

Transport Jc reached 3.1x10^4 A/cm^2 at 4.2 K and 10 T.

Hirr was increased to 16.8 T at 10 K with HCS doping.

HCS proved to be a promising dopant for high-field applications.

Abstract

A significant enhancement of Jc and Hirr in MgB2 tapes has been achieved by the in situ powder-in-tube method utilizing hollow carbon spheres (HCS) as dopants. At 4.2 K, the transport Jc for the 850C sintered samples reached 3.1x10^4, and 1.4x10^4 A/cm^2 at 10 and 12 T, respectively, and were better than those of optimal nano-SiC doped tapes. Furthermore, the Hirr for doped sample was raised up to 16.8 T at 10 K due to the carbon substitution effect. The results demonstrate that HCS is one of the most promising dopants besides nano-carbon and SiC for the enhancement of current capacity for MgB2 in high fields.