The image shows eight electrodes around a 20nm-thick magnet (white rectangle). The graphene, not shown, is less than 1nm thick and placed next to the magnet. Image: University at Buffalo.Graphene is incredibly strong, lightweight and conductive. It is not, however, magnetic – a shortcoming that has stunted its usefulness for spintronics, an emerging field that scientists say could eventually rewrite the rules of electronics, leading to more powerful semiconductors, computers and other devices.
Now, an international team led by researchers from the University at Buffalo (UB) is reporting an advance that could help overcome this obstacle. In a paper in Physical Review Letters, the team reports pairing a magnet with graphene, and inducing what they describe as 'artificial magnetic texture' in the nonmagnetic wonder material.
"Independent of each other, graphene and spintronics each possess incredible potential to fundamentally change many aspects of business and society. But if you can blend the two together, the synergistic effects are likely to be something this world hasn't yet seen," says lead author Nargess Arabchigavkani, who performed the research as a PhD candidate at UB and is now a postdoctoral research associate at SUNY Polytechnic Institute.
For their experiments, the researchers placed a 20nm-thick magnet in direct contact with a sheet of graphene, which is a single layer of carbon atoms arranged in a two-dimensional honeycomb lattice less than 1nm thick.
"To give you a sense of the size difference, it's a bit like putting a brick on a sheet of paper," says Jonathan Bird, professor and chair of electrical engineering at the UB School of Engineering and Applied Sciences and senior author of the paper.
The researchers then placed eight electrodes in different spots around the graphene and magnet to measure their conductivity. These electrodes revealed a surprise – the magnet induced an artificial magnetic texture in the graphene that persisted even in areas of the graphene away from the magnet. Put simply, the intimate contact between the two objects caused the normally nonmagnetic carbon to behave differently, exhibiting magnetic properties similar to common magnetic materials like iron or cobalt.
Moreover, it was found that these properties could completely overwhelm the natural properties of the graphene, even several microns away from the contact point of the graphene and the magnet. This distance, while incredibly small, is relatively large microscopically speaking. These findings raise important questions relating to the microscopic origins of the magnetic texture in the graphene.
Most importantly, Bird says, is the extent to which the induced magnetic behavior arises from the influence of spin polarization and/or spin-orbit coupling, which are phenomena known to be intimately connected to the magnetic properties of materials and to the emerging technology of spintronics.
Rather than utilizing the electrical charge carried by electrons (as in traditional electronics), spintronic devices seek to exploit the unique quantum property of electrons known as spin (which is analogous to the Earth spinning on its own axis). Spin offers the potential to pack more data into smaller devices, thereby increasing the power of semiconductors, quantum computers, mass storage devices and other digital electronics.
This story is adapted from material from the University at Buffalo, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.