Room-temperature molecule-based magnets

Abstract

Room–temperature magnets belonging to the Prussian blue family were obtained recently through mild chemistry methods, i.e. molecular solution chemistry at room temperature and pressure. The paper describes the rational way followed to reach this goal and the prospects opened. First, the structure of Prussian blues and how it allows variation of the electronic structure and exchange interaction through the cyanide bridge is recalled. Then it is shown how the systematic use of orbital models and simple semiempirical calculations, combined with the Néel molecular field approach, helps in increasing the Curie temperature up to room temperature in vanadium–chromium derivatives. Some methods are then proposed to improve the magnetic properties and some examples of applications in demonstrators, devices, photomagnetism, etc, are given. Finally, we mention some exciting challenges in molecular magnetism, including the preparation of single molecule magnets at room temperature.