High-density MgB2 superconducting bulk samples prepared at ambient pressure

Abstract

High-density MgB₂ (HD-MgB₂) superconducting samples (D "e 2.2 g/cm³), using different sources of magnesium powder as raw material, were synthesized in ambient pressure in a rich Mg environment. The magnesium powders used in the fabrication process include nanometer-sized magnesium particles, powders from Alfa Aesar, ordinary off-the-shelf powder, and magnesium chip. The fabrication procedure involved a double-sintering process in a rich-Mg environment. A transition temperature T_c of 39 K was observed. Samples with the equally high density and matching superconducting properties were obtained as well by a triple sintering process of the MgB₂ powder directly from Alfa Aesar.