PRECURSOR EFFECTS ON HGBA2CA2CU3O8 FORMATION UNDER HIGH-PRESSURE

The effects of the precursor on the synthesis of HgBa2Ca2Cu3O8+delta(Hg-1223) under high pressure are studied. It was observed that HgCaO2 and Hg-1212 appear in the early stage of the formation of Hg-1223. Through intercalation of Ba-Cu-O and Ca-Cu-O, HgCaO2 and Hg-1212 can be converted to Hg-1223. We found that the mixing level of Ca- and Cu-ions strongly affects the formation of Hg-1223. The existence of large CaO grains in the precursor will increase the needed synthesis temperature or synthesis time, and impurities may appear. A precursor in which Ca-ions are well reacted with other ions facilitates the formation of Hg-1223. We also found that this well-reacted precursor is insensitive to moist