Synthesis and characterization of MgB2 superconductor

Starting with Mg in two different forms, namely, powder and flakes, and B as powder, MgB2 superconductor has been synthesized using solid-state sintering method under atmospheric pressure of argon. The grain growth of MgB2 was greatly enhanced when magnesium flakes were employed. MgB2 grains having a size of up to 3 x 2 x 1 mm(3) could be retrieved from the samples synthesized using magnesium flakes. The synthesized samples have been characterized by optical microscopy, X-ray diffraction and temperature dependence of resistivity and magnetization measurements. The critical current density of the MgB2 sample synthesized using magnesium flakes was determined to be 3.9 x 10(5) A/cm(2) (5 K, 1 T), which is comparable to that reported for samples synthesized under high pressures. (C) 2001 Elsevier Science BN. Ali rights reserved.