> The Croatian scientists say that current will flow effortlessly through their material, a mixture of lead carbonate and lead and silver oxides, at up to about 30 °C.

[...]

> Danijel Djurek, a physicist at A. Volta Applied Ceramics in Zagreb, Croatia, claims that he discovered his superconducting ceramic mixture in the late 1980s. But he was unable to pin down the structure and formula of the material, and his research was interrupted by years of war, following Croatia's split from Yugoslavia.

excerpts from http://www.rexresearch.com/djurek/djurek.htm