IODINE INTERCALATION OF A HIGH-TEMPERATURE SUPERCONDUCTING OXIDE

INTERCALATION compounds are formed by inserting guest atomic or molecular species between weakly bound (usually by van der Waals forces) slabs of host materials without changing the inner crystal structure of the individual slabs. The best-known examples of host materials are graphite and the transition metal dichalcogenides1. These compounds can be made with different stage index n, where n denotes the number of slabs between adjacent intercalated layers. Intercalation provides a unique, well controlled approach to changing the physical and electronic properties of host materials over a wide range1. If intercalation can be adopted in the layered high-transition-temperature (high-T c) superconductors, it could lead to the ability to engineer their properties, with a view to investigating the mechanism responsible for high-T c superconductivity, improving the superconducting properties of the pristine materials, and developing new high-T c superconductors and superconducting devices. We report here the successful synthesis and preliminary physical characterization of a stage-1 iodine-intercalated high- T c superconductor, IBi2Sr2CaCu2Oy. © 1990 Nature Publishing Group.