Magnetism is one of the few properties that the wonder material graphene doesn’t naturally possess. However, a simple technique developed by an international research team enables magnetising large sheets of graphene with atomic precision.
The technique, described in the latest issue of the journal Science, relies on hydrogen atoms, which are virtually absorbed by the single layer of carbon atoms and transfer their magnetic moment onto it.
“We can all remember having held a magnet in our hands and seeing how it was capable of attracting or repelling another magnet at a certain distance, which was greater or smaller depending on its power,” explained Miguel Moreno Ugeda, from the CIC nanoGUNE research centre who worked on the project together with his colleagues from the Autonomous University of Madrid and the Institut Néel of Grenoble.
“What really determined this behaviour was the magnetic moment of our set of magnets. The distance at which we began to feel the appearance of a force was specified by the spatial extension of their magnetic moments, and the fact that the force should attract or repel depended on the relative orientation between them.”
The magnetic moment of hydrogen is so small that the researchers can manipulate magnetism of the graphene sheet on an atomic scale but also achieve magnetism across a larger area.
“We have managed to manipulate the individual hydrogen atoms in a controlled way and this has enabled us to freely establish the magnetic properties of selected regions of graphene,” said Moreno.
During the experiment, researchers were observing what was happening inside the graphene sheet using a tunnel-effect microscope, which allows matter to be imaged and manipulated on an atomic scale.
The results have shown that the induced magnetic moments interact strongly with each other at great distances while also abiding by a particular rule: the magnetic moments are added or neutralised depending on the relative position between the absorbed hydrogen atoms.
Researchers have been striving to make magnetic graphene ever since the wonder material was first isolated in 2004. This quest is mainly motivated by the belief that graphene is the future enabler of spintronic technology. Spintronics, which could transmit both, magnetic and electronic information at the same time, could replace current electronics in future and pave the way for the creation of a new generation of super powerful computers.