Doping Effect of Nano-Diamond on Superconductivity and Flux Pinning in MgB2

TL;DR

This study investigates how nano-diamond doping affects MgB2 superconductors, revealing suppressed transition temperature but improved flux pinning and critical current density due to microstructural changes.

Contribution

It demonstrates that nano-diamond doping enhances flux pinning and critical current density in MgB2, despite lowering the transition temperature.

Findings

Superconducting transition temperature Tc is suppressed by diamond doping.

Irreversibility field Hirr and critical current density Jc are enhanced.

Microstructure shows tightly-packed MgB2 grains with dispersed diamond nanoparticles.

Abstract

Doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is suppressed by the diamond-doping, however, the irreversibility field Hirr and the critical current density Jc are systematically enhanced. Microstructural analysis shows that the diamond-doped MgB2 superconductor consists of tightly-packed MgB2 nano-grains (~50-100 nm) with highly-dispersed and uniformly-distributed diamond nanoparticles (~10-20 nm) inside the grains. High density of dislocations and diamond nanoparticles may take the responsibility for the enhanced flux pinning in the diamond-doped MgB2.