Carbon-Coating Layers on Boron Generated High Critical Current Density in MgB₂ Superconductor

Area of Science:

• Materials Science
• Condensed Matter Physics
• Superconductivity

Background:

• Magnesium diboride (MgB₂) is a widely studied superconductor.
• Enhancing flux-pinning centers is crucial for improving superconducting properties.
• Artificial pinning centers can be engineered to optimize performance.

Purpose of the Study:

• To fabricate MgB₂ superconductors with artificial 2D flux-pinning centers.
• To investigate the microstructure and superconducting properties of carbon-coated boron precursors.
• To understand the effect of carbon layers on flux pinning and critical current density.

Main Methods:

• Preparation of boron particles with homogeneous carbon-coating.
• Fabrication of MgB₂ superconductors using the coated boron particles.
• Systematic microstructure investigation (e.g., electron microscopy).
• Measurement of critical current density and irreversibility field.

Main Results:

• Homogeneous distribution of carbon layers within the MgB₂ matrix without agglomeration.
• Carbon layer thickness is below the MgB₂ coherent length, ensuring supercurrent transparency.
• Significant increase in critical current density due to strong flux-pinning by 2D carbon layers.
• Enhanced irreversibility field attributed to carbon doping effects.

Conclusions:

• Carbon-coated boron particles effectively generate artificial 2D flux-pinning centers in MgB₂.
• The engineered microstructure leads to improved superconducting performance, including higher critical current density and irreversibility field.
• This approach offers a viable strategy for developing advanced MgB₂ superconducting materials.