Ferromagnetism in molecular materials: decamethylferrocenium tetracyanoethanide [DMeFc][TCNE] (invited)

Ferromagnetism has only recently been observed in molecular materials. We present here a summary of the ferromagnetic phenomena observed in the molecular charge transfer salt, decamethylferrocenium tetracyanoethanide (DMeFc) (TCNE), and related compounds. A spontaneous magnetization is observed in this material for T< 4.8 K, with a saturation moment in agreement with alignment of individual spins localized on the DMeFc +' and TCNE (-') ions. A comparison of these results with analogous charge transfer salts is presented. Models for the magnetic interaction in the charge transfer salts and the preparation of other molecular and/or polymeric materials with ferromagnetic exchange are presented.