Transport critical current density in Fe-sheathed nano-SiC doped MgB2 wires

TL;DR

This study demonstrates that nano-SiC doping significantly enhances the transport critical current density in Fe-sheathed MgB2 wires by creating effective pinning centers, with potential for further improvements.

Contribution

It introduces a fabrication method for nano-SiC doped MgB2/Fe wires that achieves high Jc values, surpassing previous state-of-the-art in similar wires.

Findings

Transport Jc reaches 133,000 A/cm² at 5K and 4.5T.

Transport Jc exceeds previous records by over an order of magnitude.

Doping creates intra-grain defects and nano-inclusions that improve flux pinning.

Abstract

The nano-SiC doped MgB2/Fe wires were fabricated using a powder-in-tube method and an in-situ reaction process. The depression of Tc with increasing SiC doping level remained rather small due to the counterbalanced effect of Si and C co-doping. The high level SiC co-doping allowed creation of the intra-grain defects and nano-inclusions, which act as effective pinning centers, resulting in a substantial enhancement in the Jc(H) performance. The transport Jc for all the wires is comparable to the magnetic Jc at higher fields despite the low density of the samples and percolative nature of current. The transport Ic for the 10wt% SiC doped MgB2/Fe reached 660A at 5K and 4.5T (Jc = 133,000A/cm2) and 540A at 20K and 2T (Jc = 108,000A/cm2). The transport Jc for the 10wt% SiC doped MgB2 wire is more than an order of magnitude higher than for the state-the-art Fe-sheathed MgB2 wire reported to date at 5K and 10T and 20K and 5T respectively. There is a plenty of room for further improvement in Jc as the density of the current samples is only 50%.