Molecule- and polymer-based magnets, a new frontier

Molecule- and polymer-based magnets prepared by relatively low temperature organic synthetic methodologies are of increasing interest in materials research. The three distinct models enabling the design of new molecule- and polymer-based magnetic materials are given. Bulk ferromagnetic behavior with hysteresis was first observed below the critical (Curie) temperature, Tc, of 4.8 K for [FeIII(C5Me5)2]+ [TCNE] − (Me = methyl; TCNE = tetracyanoethylene). Since then, many new classes of molecule- and polymer-based magnets have been discovered, including those with Tc above room temperature, such as V(TCNE)x· y(CH2Cl2). The important roles of spin and spatial anisotropy and also disorder are illustrated. The, anticipated properties of such molecule- and polymer-based magnetic materials may enable their use in future generations of electronic, magnetic and/or photonic/photronic devices ranging from information storage and magnetic imaging to static and low frequency magnetic shielding and magnetic induction.