Inhomogeneity of Magnesium Diboride Structure and its Effect on Critical Current Density

TL;DR

This study investigates how structural inhomogeneities like oxygen segregation and phase formation in MgB2 affect its critical current density, highlighting the role of alloying elements and nanostructuring in enhancing superconducting performance.

Contribution

It presents a detailed analysis of inhomogeneities in MgB2 and demonstrates the synthesis of a nanostructured MgB2-SiC material with significantly improved critical current density.

Findings

Oxygen segregation into Mg-B-O inclusions influences pinning.

Nanostructured MgB2-SiC exhibits high critical current density.

Alloying with SiC and Ti affects structural inhomogeneities.

Abstract

The influence of the oxygen segregation into Mg-B-O inclusions (which are oxygen enriched as compared to the matrix material) and the formation of boron enriched phases (with near MgB12 composition) in MgB2 structure on pinning in magnesium diboride and the effect of SiC and Ti alloying on the formation of structural inhomogenities in MgB2 are discussed. A nanostructural material of near theoretical density (2.7 g/cm3) based on MgB2-SiC (10 wt. percents of 200-800 nm SiC was added), which is characterized by high jc (1000000 A/cm2 in 1 T - 100000 A/cm2 in 3.5 T at 20 K and 100000 A/cm2 at 35 K) has been synthesized at 2 GPa.