Plastic Magnets to Absorb Electromagnetic Radiation in the AF's Warfighting Efforts Published May 26, 2009 By Maria Callier Air Force Office of Scientific Research ARLINGTON, Va. -- Physicists are using carbon-based molecules to create plastic magnets from organic materials that are capable of absorbing electromagnetic radiation. This technology benefits the Air Force's warfighting effort by detecting weapons hidden in clothing or in packages. The Air Force Office of Scientific Research-funded plastic magnets research led by Dr. Arthur Epstein, professor of physics and chemistry and director of Ohio State's Institute for Magnetic and Electronic Polymers, may even lead to the creation of improved electronic circuits that can find hidden flaws in electronic circuitry. These magnets are "organic" because they are formed from molecules based on carbon, hydrogen and nitrogen. They form magnetic films on electrical insulators such as glass and Teflon, and electronic materials such as silicon and gold. Because they are magnetic at room temperatures -- even up to 250 degrees Fahrenheit -- they may be used in a variety of environments. Epstein observed, "These films absorb electromagnetic radiation such as microwaves and terahertz rays, or T-rays, which can be used to look through wrappings for weapons. While they can image like x-rays, they have the important advantage of causing little or no harm to living tissue in contrast to damage caused by x-rays." Plastic magnets are being made by using a technique known as "chemical vapor deposition" (CVD), which is a process that produces high-purity, high-performance solid materials. The CVD process can only be accomplished by using a room that is nearly without dirt or dust in a space called a "glove box." Epstein's team built 100 of these oxygen- and moisture-free rooms. Any other environment with even minimal dust and dirt could lead to large defects and would limit the use of these magnets in new technology. Plastic magnets share properties with conventional magnets because of the chemical building blocks used in vapor deposition. Among plastic magnets' unique properties are the ability to control the magnetism with light and to have the 'spins' of the electrons be pointed the same direction. This is a rare property of matter that has never before been found in a semiconductor until now. When the plastic magnets were initially produced by Epstein's colleague, Dr. Joel S. Miller of the Department of Chemistry at the University of Utah, they were so unstable they were flammable in the air. "By coating magnets with a nonmagnetic and nonconducting polymer, we have been able to make them more stable. In fact, they may now be in ambient air, which is a gaseous mixture made up of nitrogen and oxygen, for hours without becoming combustible or decreasing their performance as detectors or electronic and magnetic materials," he noted. Epstein remains optimistic about the future of plastic magnets and their use in Air Force technology because his research is continuing unabated and the chemistry of the materials is evolving so that magnetic, electronic and photonic properties will continue to improve.