Bulk ferromagnetic properties

As far as organometallics are concerned, and important exception is represented by the (per)alkylated metallocenes and the related bis(arene) complexes of various transition metals. These compounds have been intensively studied in connection with the magnetic properties of their CT complexes, mainly by Miller and co-workers [11]. These studies led to the discovery of the first organometallic compound displaying bulk ferromagnetic properties (vide infra). 

Interest is maintained ia these materials because of the combination of mechanical, corrosion, electric, and magnetic properties. However, it is their ferromagnetic properties that lead to the principal appHcation of glassy metals. The soft magnetic properties and remarkably low coercivity offer tremendous opportunities for this appHcation (see Magnetic materials, bulk Magnetic materials, thin film). 

This section is devoted to four main topics spin-Peierls systems, spin-ladder systems, systems exhibiting ferromagnetic interaction, and bulk ferromagnets. To our knowledge, no dithiolene-based films (including LB films) have been studied for their ferromagnetic properties and no patent has claimed the use of these materials in this area. 

Several CT complexes of metal bis(arene) compounds containing, among others, the familiar organic acceptor TCNQ have been reported [71]. None of these materials has been shown to display physical properties superior to those of the metallocene systems. One very important exception is related to the reaction of bis(benzene) vanadium (which is isoelectronic with [MnCpf ]) with TCNE, which affords a material with unprecedented properties [72]. The amorphous material obtained displays bulk ferromagnetism at room temperature and its even exceeds the decomposition temperature of the sample of about 350 K. The compound is no longer an arene complex as it has an empirical composition corresponding to V(TCNE)2 1/2(CH2C12). 

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