Synthesis and structural properties of AgxHgBa2CuO4 + δ (0 ≤ x ≤ 0.5) superconducting materials

A series of AgxHgBa2CuO4 + δ (0 ≤ x ≤ 0.5) materials of tetragonal phase are synthesized from the precursor Ba2CuO3 and Ag2O by solid state reaction. The maximum reduction in cell volume (~1%) and superconducting transition temperature occur below 0.1 mole fraction of Ag. For this concentration of Ag, about 5% Hg sites may be occupied by the Ag atoms. Scanning electron microscopy (SEM) shows a grain size distribution from less than 1 to 10 μm in these materials. Transport critical current density varies with Ag concentration and a maximum value of 45 A cm−2 at 77 K is observed for the Ag0.5HgBa2CuO4 + δ material.