Exceeding the Bounds of Magnetism?

There is something special about Fe16N2. Since the early 70’s, scientists from around the globe have obsessed over the molecular harmony of iron and nitrogen. This compound is not the primary constituent of the next anti-aging elbow cream or mentholated septum moistener. Fe16N2 may prove to be the most magnetic substance known to man – as much as 18% more than iron cobalt. If this is true, it’s a really big deal. Everything from Maglev to microcircuitry could benefit.

Despite the odd hint from anomalous data or experimental variance, however, no reliable evidence exists which supports that claim. Among others, the electronics monolith Hitachi struggled for years to make sense of data that popped up when experimenting with Fe16N2 that suggested an extreme degree of magnetism. Ultimately, their results were not reproducible, and the hype surrounding the molecule underwent the systemic ebb and flow typical of fringe science. Fe16N2 is back in the news because researches from the University of Minnesota appear close to overturning the historical shortcomings of this molecule.

By fine tuning their technique, these scientists managed to create a reliable means of growing Fe16N2 in laboratory conditions. This molecule exists as a fragile crystalline structure that is normally metastable, breaking down into other compounds very quickly. At the University of Minnesota, they are able to maintain Fe16N2 long enough to accurately measure the strength of its magnetism. So how do you measure the magnetism of a transient crystal? The researchers employ a technique called x-ray magnetic circular dichromism. This method works by comparing the polarization of x-ray light to see if it bends to the left or right. Combining that with the magnitude of the bend can accurately tell researchers its magnetic strength and polarity. Applying this technique, Fe16N2 consistently measures as the most magnetic substance known to man by a degree of about 18%.

This is a promising step, but many scientists in the field are skeptical given Fe16N2‘s turbulent history. There is near unanimity, though, in the appreciation  that should these results prove verifiable, this is an amazing breakthrough. It might even be enough to extend  the lifespan of magnetic drives a few more years. But given its delicate nature, it seems a lot of work remains before it could be viable in practical application. Regardless, the siren’s song of Fe16N2 and enhanced magnetism has lured in another generation of minds, and it will be exciting to see what comes of it.


~ by Wil Finley on March 21, 2010.

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