The mercury-based oxide superconductor, HgBa2Ca3Cu4Oy phases was synthesized by a controlled vapor/solid reaction technique using high-purity powders of HgO, BaO, CaO and CuO as starting materials. Two types of bars, with different cation ratios of Hg:Ba:Ca:Cu=0:2:2:3 and 1:2:2:3, were heated in an evacuated quartz tube. The resulting HgBa2Ca3Cu4Oy sample had a Tc of 123 K and lattice parameters a=3.852(2) Å and c=19.01(4) Å with a volume fraction of 83% of the total shielding signal. The formation condition was widely investigated, showing that the higher heating temperature and longer heating time lead to the formation of the HgBa2CanCun-1Oy phase with a higher number n of Cu-O2 planes in a unit cell.
ASJC Scopus subject areas