SUPERCONDUCTIVITY IN A LAYERED PEROVSKITE WITHOUT COPPER

FOLLOWING the discovery of superconductivity at similar to 30K in La2- xBaxCuO4 (ref. 1), a large number of related compounds have been found that are superconducting at relatively high temperatures. The feature common to all of these materials is a layered crystal structure based on a perovskite template and containing planar networks of copper and oxygen. This raises the question of whether superconductivity can occ ur in layered perovskites that do not contain copper. To the best of o ur knowledge, no such material has been found to date, despite nearly a decade of searching. We describe here the discovery of superconducti vity in Sr2RuO4, a layered perovskite isostructural with La2-xBaxCuO4 (Fig. 1). Our results demonstrate that the presence of copper is not a prerequisite for the existence of superconductivity in a layered pero vskite. But the low value of the superconducting transition temperatur e (T-c= 0.93 K) points towards a special role for copper in the high-t emperature superconductors.