Associate 1996-97

Gregory S. Girolami


Synthesis of New Molecular Magnets

Professor Girolami has been developing a new approach to the manufacture of magnets, one that involves the use of molecular species as “building blocks." His approach, which involves the controlled assembly of molecular starting materials into three-dimensional arrays, has the advantage that the magnets can be prepared at room temperature rather than the high temperatures characteristic of metallurgical and ceramic processing methods. By varying the structure of the molecular building blocks, he has been able to control both the three-dimensional architecture and the magnetic properties of the resulting solid product.

Professor Girolami and his research group have been studying chemical analogues of the well-known dye Prussian blue, which is the pigment used in blueprints. Although Prussian blue contains iron, it is not magnetic under normal conditions; it becomes magnetic only when cooled to temperatures below 5 degrees Kelvin. By replacing the iron atoms with other elements, Professor Girolani has been able to obtain solids that retain their magnetism at higher temperatures. Their most interesting results have been achieved by replacing the iron atoms with vanadium or chromium; one of these vanadium-containing solids remains magnetic at room temperature. These materials have magnetic properties similar to those used as magnetic recording media in cassette tapes and optical drives. One long-range goal of Professor Girolami's research is to develop an optically-transparent magnet that operates at room temperature. Such a material could have a variety of new and interesting applications.