Critical current density in the MgB₂ nanoparticles prepared under autogenic pressure at elevated temperature

This Letter reports on obtaining MgB₂ nanoparticles revealing an intra-granular enhanced critical current density (J_C ≥ 10⁸ A/cm²) for the undoped sample. A rapid, single-stage, high yield, reproducible, straightforward, scalable, and competent approach at 750 °C is described herein for the synthesis of superconducting MgB₂ nanoparticles. The magnetization studies indicated clearly the existence of bulk superconductivity in MgB₂ nanoparticles at T_C ∼ 38 K. Electron spin resonance and microwave absorption study substantiated the paramagnetic nature of the MgB₂ nanoparticles in the normal state. The plausible reaction mechanism leading to the formation of MgB₂ is explained.