Enhanced higher temperature (20-30 K) transport properties and irreversibility field in nano-Dy2O3 doped advanced internal Mg infiltration processed MgB2 composites

TL;DR

This study demonstrates that nano-Dy2O3 doping in MgB2 composites significantly enhances high-temperature transport properties and irreversibility fields, especially at 20-30 K, through improved critical current densities and layer growth.

Contribution

The paper introduces a novel doping approach with nano-Dy2O3 in MgB2 composites, achieving notable improvements in high-temperature superconducting performance via the AIMI process.

Findings

Critical current densities increased with Dy2O3 doping.

Irreversibility fields were significantly enhanced at 20-30 K.

MgB2 layer growth was improved by Dy2O3 doping.

Abstract

A series of MgB2 superconducting composite strands co-doped with Dy2O3 and C were prepared via an advanced internal Mg infiltration (AIMI) route.The transport properties and MgB2 layer growth were studied in terms of the Dy2O3 doping level, reaction temperature, and reaction time. Transport studies showed that both critical current densities, Jcs, and irreversibility fields, Birrs, were increased with Dy2O3 doping. The highest layer Jc was 1.35 x 10^5 A/cm2 at 4.2 K, 10 T, 30% higher than that of the best AIMI wires without Dy2O3 doping. The highest "non-barrier" Jc reached 3.6 x 10^4 A/cm2 at 4.2 K, 10 T, which was among the best results reported so far. The improvements were even more pronounced at higher temperatures where the field at which the layer Jc reached 10^4 A/cm2 was pushed out by 0.9 T at 20 K, 1.2 T at 25 K, and 1.4 T at 30 K. While little or no enhancement in Birr was seen at 10 K and 15 K, the increases in Jc at higher temperatures were consistent with observed increases in Birr of 17% at 20 K, 44% at 25 K, and 400% at 30 K. Also, there were some indications that the reaction and layer growth of MgB2 was enhanced by Dy2O3 doping.