Nanostructured compact bulk MgB₂ cryo-magnets with record-high critical currents and trapped magnetic fields

Area of Science:

• Materials Science
• Condensed Matter Physics
• Superconductivity

Background:

• Magnesium diboride (MgB₂) is a promising superconductor.
• Enhancing its performance, particularly critical current density (Jc) and trapped magnetic fields, is crucial for practical applications.
• Current methods for improving MgB₂ often face limitations in defect control.

Purpose of the Study:

• To develop a novel approach for engineering nanoscale defects in MgB₂.
• To significantly enhance the superconducting performance of MgB₂ through controlled defect creation.
• To investigate the impact of specific nanoscale inclusions on Jc and magnetic field trapping.

Main Methods:

• Spark plasma sintering (SPS) was employed for material processing.
• Nanoscale defects were engineered by incorporating MgB₂O particles through silver addition, carbon doping, and magnesium excess.
• Superconducting properties, including self-field critical current density (Jc) and trapped magnetic fields, were systematically measured.

Main Results:

• Achieved a self-field critical current density (Jc) of 1.2 MA/cm² at 10 K.
• Observed a single peak in the normalized pinning force density diagram at b = 0.3.
• Demonstrated exceptional trapped field values: 4.21 T at 11 K (single bulk) and up to 6 T at 10 K (triple-stacked cryo-magnet).

Conclusions:

• The novel nanoscale defect engineering approach significantly enhances MgB₂ superconductor performance.
• The results demonstrate a new paradigm for designing high-performance superconductors.
• This advancement has broad implications for superconductors, nanomaterials, and future energy systems.