Materials physicists from the University of Minnesota have found a super-magnetic material comprising 16 iron atoms and two of nitrogen. An x-ray analysis of the compound showed that six iron atoms are clustered around each nitrogen, with two more located between the two clusters. The researchers said electrons flowing between the clusters act like they do in ordinary iron, but within the clusters, the electrons tend to be localized, and this increases the magnetism.
The findings were reported at the American Physical Society’s meeting this month. Researchers say it had been thought since the 1970s that the material, Fe16N2, was extremely magnetic, but no one had ever been able to confirm the theory. Complicating the problem is that Fe16N2 is metastable and tends to form other crystal structures. The Minnesota researchers created a thin film of the material and used x-ray magnetic circular dichroism to measure its magnetization. This technique directly detects the localized electrons, and is thus less sensitive to volume effects than the earlier methods.
But it doesn't look like you'll be buying Fe16N2 PM motors anytime soon. The applications for the material that researchers have in mind are thin-film heads for hard disk drives. And though they have managed to produce samples for research purposes, they say they don't yet have a way of mass producing the stuff.
The Physorg.com site ran a story on the findings: