- 17 Septembr 2005 -

Magnetic diamond particles

Researchers have reported a technique to make magnetic diamond particles only 4-5nm across which could be used in fields ranging from medicine to information technology.

Scientists are becoming increasingly interested in the prospect of creating metal-free magnets, particularly from carbon-based materials which have a number of advantages over their metal counterparts.

“Carbon is lightweight, very stable, simple to process, and less expensive to produce,” says Saikat Talapatra, a post-doctoral research associate with the Rensselaer Nanotechnology Center at Rensselaer Polytechnic Institute and the lead author of the study published in Physical Review Letters.

Co-researchers come from NASA Ames Research Center in California; Richmond, Va.-based Philip Morris USA; and the University at Albany.

Magnetic nanocarbons could make promising structures for high-density memory devices and in quantum computers. And because carbon materials are generally compatible with living tissue, these nanostructures could be useful in medical applications such as MRI and the targeted drug delivery to the body.

Researchers have long known that defects and irregularities in pure carbon materials can give rise to electrons that are not paired with other electrons. Each “unpaired” electron produces a magnetic field by its spinning, and when all of the spins align, the material itself becomes magnetic.

Talapatra and his colleagues have developed a way to modify the structure of carbon in a controlled manner by firing clusters of atoms at the diamond particles. This produces magnetism at room temperature, and the total strength of the magnetism depends on the amount and type of atoms used.

The next step, according to Talapatra, is to calculate how the types of defects and their concentration in the pure carbon structure affect the magnitude of magnetism.

“We are also working toward developing simpler ways to make magnetic nanocarbons in a more controlled fashion,” he says. “The long-term goal is to show some real applications using these structures.”

The research was funded by NASA, Philip Morris USA, and the National Science Foundation.