Molecular magnetic semiconductors, metals and superconductors:BEDT-TTF salts with magnetic anions

Abstract

Molecular charge-transfer salts that consist of alternating layers of organic donor molecules and inorganic anions offer the opportunity of bringing together in the same crystal lattice conduction electrons localised on the donor sublattice and magnetic moments localised on the inorganic anions. A wide range of such compounds is formed by the donor molecule BEDT-TTF [bis(ethylenedithio)tetrathiafulvalene]. Some are semiconductors, others are metals while one is a superconductor, the first containing paramagnetic 3d moments. The structures, magnetic and conductivity properties of examples from each category are reviewed.