Superconducting performance of ex-situ SiC-doped MgB2 mono-filamentary tapes

TL;DR

This study demonstrates that adding SiC to MgB2 tapes and synthesizing at lower temperatures significantly enhances their superconducting properties, especially the critical current density and field performance, despite a slight decrease in transition temperature.

Contribution

It introduces a method of SiC doping and optimized synthesis temperature to improve superconducting performance of MgB2 tapes, with detailed analysis of resulting properties.

Findings

Superconducting parameters (Hc2, Hirr, Jc) are significantly improved with SiC doping.

Lower synthesis temperature (700°C) enhances superconducting performance.

SiC doping reduces Jc anisotropy and slightly decreases Tc.

Abstract

We report on the superconducting performance of the ex-situ SiC doped MgB2 monofilamentary tapes. Polycrystalline powders of MgB2 doped with 5 and 10 wt% SiC were synthesized by conventional solid-state reaction route and characterized for their superconducting performance. It is found that superconducting parameters i.e. upper critical field (Hc2), irreversibility field (Hirr) and critical current density (Jc) are all improved significantly with SiC addition. Also it was found that relatively lower synthesis temperature (700 C) resulted in further improved superconducting parameters. As synthesized powders are used for ex-situ powder-in-tube (PIT) monofilamentary tapes and superconducting parameters are determined. Albeit the superconducting transition temperature (Tc) is decreased slightly (2K) for SiC doped tapes, the superconducting performance in terms of critical current density (Jc), being determined from both magnetization and transport measurements, is improved significantly. In particular the SiC doped and 700 {\deg}C synthesized MgB2 tapes exhibited the transport Jc of nearly 10^4 A/cm2 under applied fields of as high as 7 Tesla. Further it is found that the Jc anisotropy decreases significantly for SiC doped tapes. Disorder due to substitution of C at B site being created from broken SiC and the presence of nano SiC respectively in SiC added ex-situ MgB2 tapes are responsible for decreased anisotropy and improved Jc(H) performance.