SUPERCONDUCTING MERCURY-BASED CUPRATE FILMS WITH A ZERO-RESISTANCE TRANSITION-TEMPERATURE OF 124 KELVIN

The synthesis of high-quality films of the recently discovered mercury-based cuprate films with high transition temperatures has been plagued by problems such as the air sensitivity of the cuprate precursor and the volatility of Hg and HgO. These processing difficulties have been circumvented by a technique of atomic-scale mixing of the HgO and cuprate precursors, use of a protective cap layer, and annealing in an appropriate Hg and O-2 environment. With this procedure, a zero-resistance transition temperature as high as 124 kelvin in c axis-oriented epitaxial HgBa2CaCu2O6+delta films has been achieved.