Large Upper Critical Field and Irreversibility Field in MgB2 wires with SiC additions

TL;DR

This study investigates how SiC additions of different particle sizes enhance the upper critical and irreversibility fields in MgB2 wires, with optimal results at specific heat treatments.

Contribution

It demonstrates that SiC doping with varying particle sizes significantly improves the magnetic field thresholds of MgB2 wires, identifying optimal processing conditions.

Findings

Maximal Hirr of 29 T with 15 nm SiC at 725°C

Maximum Bc2 exceeding 33 T with optimized SiC doping and heat treatment

Strands with 200 nm SiC achieved Hirr of 25.4 T and Bc2 of 29.7 T at 800°C

Abstract

Resistive transition measurements are reported for Magnesium diboride strands with SiC dopants. The SiC was added as 10 mol of SiC to 90 mol of binary magnesium diboride. Three different SiC powders were used, the average particle sizes were 200 nm, 30 nm, and 15 nm. The strands were heat treated for times ranging from 5 to 30 minutes at temperatures from 675 to 900. Strands with 200 nm size SiC additions had Hirr and Bc2 which maximized at 25.4 T and 29.7 T after heating at 800C for 30 minutes. The highest values were seen for a strand with 15 nm SiC heated at 725C for 30 minutes which had a Hirr of 29 T and a Bc2 higher than 33 T