Superconductivity, Antiferromagnetism, and Phase Diagram of a Series of Organic Conductors: λ-(BETS)2FexGa1-xBryCl4-y

Organic conductors based on the bis(ethylenedithio)tetraselenafulvalene(BETS) are of interest because they display not only superconducting and magnetic transitions but also, as recently reported, unprecedented superconductor to insulator transitions. Here is presented the electrical and magnetic properties for two series of λ-(BETS)2FexGa1–xBryCl4–y, one system with fixed Br content, the other with fixed Fe content. This systematic study includes the superconductor to insulator transition, and also a superconductor to metal transition, which has never been previously reported for an organic conducting system.