Phase Evolution and Critical Temperature of MgB2 Superconductor Made of β-Rhombohedral Boron with Temperature Sintering Variation

Abstract

We report the phase formation and electrical resistivity of MgB2 superconductor samples. Method of synthesis was conventional solid-state reaction employing crystalline β-rhombohedral boron (B) and magnesium (Mg) with a stoichiometric ratio of Mg:B=1:2. The two precursors were mixed and sintered at various temperatures from 600°C to 900°C for an hour. All samples were characterized employing XRD, SEM, and Cryogenic Magnetometer. It is shown that the MgB2 phase begins to form at a sintering temperature of 700°C. The highest peak intensity of the MgB2 phase was observed in a sample sintered at 900°C indicates the largest fraction of the superconducting phase among all synthesized samples. Electrical resistivity values were carried out to investigate the superconducting properties of the samples. It is also shown the samples sintered at a temperature of 800°C and 900°C possess superconducting properties with a critical temperature of ~ 43 K