D. Gatteschi - Böcker

One of the major challenges of science in the last few years of the second millennium is learning how to design materials which can fulfill specific tasks. Ambitious as it may be, the possibilities of success are not ne~li~ble provided that all the different expertises merge to overcome the limits of eXIsting disciplines and forming new paradigms science. The NATO Advanced Research Workshop on "Magnetic Molecular Materials" was organized with the above considerations in mind in order to determine which are the most appropriate synthetic strategies, experimental techniques of investigation, and theoretical models which are needed in order to develop new classes of magnetic materials which are based on molecules rather than on metallic or ionic lattices. Why molecules? The answer may be obvious: molecular chemistry in principle fine can tune the structures and the properties of complex aggregates, and nature already provides a large number of molecular aggregates which can perform the most disparate functions. The contributions collected in this book provide a rather complete view of the current research accomplishments of magnetic molecular materials. There are several different synthetic approaches which are followed ranging from purely organic to inorganic materials. Some encouraging successes have already been achieved, even if the critical temperatures below which magnetic order is observed still are in the range requiring liquid helium.

This work reviews the state of the art in the area of molecular magnetism. It is organized in two parts, the first of which introduces the basic concepts, theories and physical techniques required for the investigation of the magnetic molecular materials, comparing them with those used in the study of classical magnetic materials. Here the reader will find: (i) a detailed discussion of the electronic processes involved in the magnetic interaction mechanisms of molecular systems, including electron delocalization and spin polarization effects; (ii) a presentation of the available theoretical models based on spin and Hubbard Hamiltonians; and (iii) a description of the specific physical investigative techniques used to characterize the materials. The second part presents the different classes of existing magnetic molecular materials, focusing on the possible synthetic strategies developed to date to assemble the molecular building blocks ranging from purely organic to inorganic materials, as well as on their physical properties and potential applications.These materials comprise inorganic and organic ferro- and ferrimagnets, high nuclearity organic molecules and magnetic and metallic clusters, spin crossover systems, charge transfer salts (including fulleride salts and organic conductors and superconductors), and organized soft media (magnetic liquid crystals and Langmuir-Blodgett films).

The second part presents the different classes of existing magnetic molecular materials, focusing on the possible synthetic strategies developed to date to assemble the molecular building blocks ranging from purely organic to inorganic materials, as well as on their physical properties and potential applications.