SUPERCONDUCTIVITY ABOVE 100 K IN COMPOUNDS CONTAINING HG

The results of studies of new Hg based cuprate superconductors are rep orted. Several members of a new family of (Hg,T1)(Ba,Sr)Can-2CunOx hig h temperature superconductors have been synthesized. These compounds, which are analogs to the Hg-Ba-Ca- and T1-Ba-Ca- layered cuprates, are multi-phased and have superconducting transition temperatures above 1 00 K. incorporation of Hg appears to stabilize several of the T1-compo unds, including a double layer. T1/Sr system, in a manner similar to t he role that Pb plays in the T1/Sr- and Bi/Sr-systems. It has been sug gested that recent reports of resistive T-c's above 200 K in Hg based samples are due to the presence of free Hg. Magnetization measurements of such a sample confirm this hypothesis.