Properties of MgB2 thin films with carbon doping

TL;DR

This study explores how carbon doping affects the structural and superconducting properties of MgB2 thin films, revealing increased critical fields and pinning, which are promising for high magnetic field applications.

Contribution

It introduces a carbon doping method during film growth and analyzes its effects on MgB2's properties, highlighting potential for high-field superconductor applications.

Findings

Carbon doping increases upper critical field dramatically.

Resistivity and Tc decrease with more carbon.

Doped films exhibit stronger vortex pinning.

Abstract

We have studied structural and superconducting properties of MgB2 thin films doped with carbon during the hybrid physical-chemical vapor deposition process. A carbon-containing metalorganic precursor bis(cyclopentadienyl)magnesium was added to the carrier gas to achieve carbon doping. As the amount of carbon in the films increases, the resistivity increases, Tc decreases, and the upper critical field increases dramatically as compared to the clean films. The self-field Jc in the carbon-doped films is lower than that in the clean films, but Jc remains relatively high to much higher magnetic fields, indicating stronger pinning. Structurally, the doped films are textured with nano-grains and highly resistive amorphous areas at the grain boundaries. The carbon doping approach can be used to produce MgB2 materials for high magnetic field applications.