Materials scientists successfully combine the best of two worlds

24 May 2013

Which materials should we invest in for future technology? Organic molecules with their excellent magnetic properties, or perhaps graphene which can give us many magnitudes faster transistors? Researchers from Uppsala and Berlin now show, in the esteemed journal Advanced Materials, that both materials can be combined to create the best of both worlds.

Organic molecules such as for example iron porphyrin have excellent magnetic properties which make them particularly suitable for molecular spin transistors. Graphene is another material with favourable properties; high speed electron transport which allows graphene-based transistors to be many magnitudes faster than current technology.

Graphene is a carbon based material which is only one atomic layer thick. Electron transport through graphene works in a way which makes it much faster than in current semiconductors. In molecular spintronics, focus lies on building the smallest spin transistors, consisting of only one or a few molecules. These can transport electric current based on the molecule’s spin magnetic moment. Combining the two materials could open the door to new technological possibilities. Researchers at Uppsala University and Freie Universität Berlin now show that organic magnetic molecules can be combined with graphene.

The researchers used metal porphyrin molecules similar to iron porphyrin, which can be found as an active part in the oxygen transport of haemoglobin in blood. The metal porphyrin molecule was adsorbed to graphene, in turn placed on a layer of nickel. Through detailed magnetic measurements the group in Berlin could conclude that the metal porphyrin molecule on graphene retained its special spin properties, which now also could be controlled by magnetising in the nickel layer.

The Uppsala researchers could then show that it was in fact graphene that gave the important magnetic connection between the porphyrin and the nickel layer. Through thorough computer simulation they clarified that graphene transfers the spin information between the nickel layer and the metal porphyrin and that even the graphene layer itself becomes magnetic.

“Our discovery suggests that it is possible to construct new hybrid materials which combine the unique properties of graphene and metal organic molecules. This can be further developed and open up the realisation of hybrid electronics in the future”, says Professor Peter Oppeneer, who has led the project together with Professor Wolfgang Kuch in Berlin.

Read the article at Advanced Materials online: http://onlinelibrary.wiley.com/doi/10.1002/adma.201205275/abstract