Properties of MgB2 superconductor chemically treated by acetic acid

Commercial Alfa Aesar MgB2 powder was chemically treated by acetic acid with the aim of MgO removing. Single-core MgB2/Fe ex situ wires have been made by powder-in-tube (PIT) process using the powders treated with different acid concentration. All samples were annealed in argon at 950 °C/0.5 h. Differences in transition temperatures and critical currents of acetic acid treated MgB2 are related to the normal state resistivity, effective carbon substitution from the organic solvent and the active area fraction (grain-connectivity).