Metal-free organic magnets were first discovered 10 years ago, but their magnetic properties were fleeting, disappearing at temperatures only slightly above absolute zero. Now in a discovery made quite by accident, researchers have found the first example of an organic magnet that perseveres at higher temperatures. The findings appear today in the journal Nature.
Tatiana Makarova of the Ioffe Physico-Technical Institute in Russia and colleagues were searching for superconductivity in a polymer of fullerenea cage-like molecule comprised of 60 carbon atomswhen they realized that their product demonstrated magnetic qualities at room temperature. The magnetization in some of the samples, the scientists write, was strong enough for them to be lifted off a table surface by a small magnet. The researchers suggest that the high-pressure, high-temperature processes required to create the polymer form of C60 results in a magnetically ordered state, although they are not sure exactly how this happens. "We are at present performing a detailed comparative studyin an attempt to determine more precisely the causes of the magnetic behavior reported here," they write.
In an accompanying commentary, Fernando Palacio of the University of Zaragoza in Spain discusses the controversy surrounding the new report. A number of questions, such as how the magnetic moments in the polymer arise and why the magnetization is less than might theoretically be expected, still need to be answered, he writes. He does concede, however, that "if confirmed, this result will represent a breakthrough in the magnetism of metal-free materials."