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nanotimes News in Brief Graphene //

Graphene Reveals its Magnetic Personality © Based on Material by Condensed Matter Physics Group, UK

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cientists from The University of Manchester (UK) have now shown that an organic matter can

behave like a fridge magnet. The Manchester resear- chers took nonmagnetic graphene and then either ‘peppered’ it with other nonmagnetic atoms like fluorine or removed some carbon atoms from the chicken wire. The empty spaces, called vacancies, and added atoms all turned out to be magnetic, ex- actly like atoms of, for example, iron.

“It is like minus multiplied by minus gives you plus”, says Dr Irina Grigorieva.

Demonstrating its remarkable properties won Man- chester researchers the Nobel Prize in Physics in 2010. This latest research led by Dr Irina Grigorieva and Professor Sir Andre Geim (one of the Nobel prize recipients) could prove crucial to the future of graphene in electronics.

The researchers found that, to behave as magnetic atoms, defects must be far away from each other and their concentration should be low. If many defects are added to graphene, they reside too close and cancel each other’s magnetism. In the case of vacan- cies, their high concentration makes graphene disin- tegrate. Professor Geim said: “The observed magne- tism is tiny, and even the most magnetized graphene samples would not stick to your fridge.”

“However, it is important to reach clarity in what is possible for graphene and what is not. The area of magnetism in nonmagnetic materials has previously had many false positives. The most likely use of the found phenomenon is in spintronics. Spintronics devices are pervasive, most notably they can be found in computers’ hard disks. They function due to coupling of magnetism and electric current.”

“Adding this new degree of functionality can prove important for potential applications of graphene in electronics,” adds Dr Grigorieva.

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R. Nair, M. Sepioni, I-Ling Tsai, O. Lehtinen, J. Keinonen, A. Krasheninnikov, T. Thomson, A. Geim and I. Grigo- rieva: Spin-half paramagnetism in graphene induced by point defects, In: Nature Physics AOP, January 10, 2012, DOI:10.1038/NPHYS2183: http://dx.doi.org/10.1038/NPHYS2183