Plastic Magnets Attract More Than Warfighter Attention

  • Published
  • By Maria Callier
  • AFOSR
ARLINGTON, Va. --  AFRL is funding the research of plastic magnets, a technology of value to warfighters in detecting weapons hidden in clothing or packages. Led by Dr. Arthur Epstein, professor of physics and chemistry and director of the Institute for Magnetic and Electronic Polymers at The Ohio State University, a team of physicists is creating the plastic magnets from organic materials capable of absorbing electromagnetic radiation. In addition to aiding weapons detection, this research may lead to improved electronic circuits that can find hidden flaws in electronic circuitry.

What makes the magnets "organic" is their constituent carbon-, hydrogen-, and nitrogen-based molecules, which form magnetic films on electrical insulators (e.g., glass and Teflon) and electronic materials (e.g., silicon and gold). Because they exhibit magnetism in conditions ranging from room temperature to 250°F, the magnets are suitable for use in a variety of environments.

Creating the plastic magnets involves a technique known as chemical vapor deposition (CVD), a process that produces high-purity, high-performance solid materials. Successful CVD requires a pristine environment--a room with no oxygen or moisture and virtually free of dirt and dust. Any other, less-than-pure conditions can precipitate substantial defects that could limit the technology's use. Such controlled-climate spaces are known as "glove boxes," and Dr. Epstein's team built 100 of them.

The chemical building blocks of vapor deposition produce plastic magnets that not only share properties with conventional magnets, but display characteristics all their own. These unique properties translate to novel capabilities, including the means to control their magnetism with light, as well as to point the "spins" of their electrons in the same direction--a rare property of matter heretofore not found in a semiconductor.

Over time, the physicists have been able to improve the magnets' initial instability by coating them with a nonmagnetic and nonconducting polymer. Consequently, they can now withstand exposure to ambient air (a gaseous mixture comprising nitrogen and oxygen) for hours without becoming combustible or decreasing their detection performance. The magnetic, electronic, and photonic properties will further improve as the chemistry of the involved materials--and with it, this research--continues to evolve.