Effective synthesis of HgBa sub(2)Ca sub(2)Cu sub(3)O sub(8+y): the highest T sub(c) superconductor

An Hg-1223 with 60%-70% phase purity is prepared via a simplified route. The material shows a sharp onset of diamagnetism at a T sub(c) of 135K. In addition, HREM has shown this sample to be of good quality with a lack of observable defects, possibly explaining the sharpness of the superconducting transition. The preparation is carried out in a single-step route from mono-oxides. With the difficulty in preparing good quality precursors, the preparation of Hg-1223 in a single-step reaction is significant, and it is shown that once this approach is adopted, the synthesis itself becomes relatively simple.