Graphene with artificial magnetic texture could enable more rugged electronic devices

Graphene is incredibly strong, conductive, light, and the list of its superior properties goes on.

The image shows eight electrodes around a 20 nm thick magnet (white rectangle) and graphene (white dotted line). Image credit: University of Buffalo.

However, graphene lacks one main property – it is not magnetic, and this drawback has eclipsed its applications in spintronics, an ascending field that the researchers say could eventually rewrite the rules of electronics, which would result in more robust computers, semiconductors and other devices. .

Led by the University of Buffalo (UB), an international group of researchers have now reported progress that could help overcome this hurdle.

A study recently published in the Physical examination letters The journal explains how a magnet was paired with graphene to induce a so-called “artificial magnetic texture” in the non-magnetic miracle material.

Independently of each other, graphene and spintronics each have incredible potential to fundamentally change many aspects of business and society. But if you can mix the two together, the synergistic effects are probably something this world has yet to see..

Nargess Arabchigavkani, lead study author and associate postdoctoral researcher, SUNY Polytechnic Institute

Arabchigavkani carried out the study while she was a doctoral student at UB.

The other authors of the study are from UB, King Mongkut Institute of Technology in Ladkrabang, Thailand, Chiba University in Japan, China University of Science and Technology, University of Nebraska Omaha, University of Nebraska Lincoln, and University of Uppsala in Sweden.

The researchers carried out their experiments by placing a 20nm thick magnet in direct contact with a sheet of graphene – a single layer of carbon atoms aligned in a two-dimensional honeycomb array less than 1 nm.

To give you an idea of ​​the size difference, it’s a bit like putting a brick on a sheet of paper.

Jonathan Bird, PhD, study lead author, professor and director of electrical engineering, School of Engineering and Applied Sciences, University of Buffalo

Next, the researchers placed eight electrodes in various locations near the graphene and the magnet to quantify their conductivity.

A surprising attribute was revealed by the electrodes: the magnet activated an artificial magnetic texture in the graphene which remained even in the regions of the graphene far from the magnet. Put simply, the intimate contact present between the two objects caused the usually non-magnetic carbon to behave in an unusual way, displaying magnetic properties quite similar to those of common magnetic materials such as cobalt or iron.

It has been found that these properties can entirely surpass the natural properties of graphene, even when observed several microns from the point of contact of the magnet and graphene. Although this distance (one micron equals one millionth of a meter) is incredibly small, it is relatively huge in microscopic terms.

The results of the study lead to essential questions concerning the microscopic origins of the magnetic texture of graphene.

More importantly, Bird said this is the extent to which induced magnetic behavior emerges from the impact of spin polarization and / or spin-orbit coupling – phenomena known to be closely related to the magnetic properties of materials. and also to the rise of spintronics technology.

Instead of using the electrical charge carried by electrons (similar to conventional electronics), spintronic devices make use of the special quantum property of electrons called spin (which is similar to the earth’s rotation on its own axis) .

Spin provides the ability to aggregate more information into smaller devices, thereby increasing the power of quantum computers, mass storage devices, semiconductors, and other digital electronics.

The study was financially supported by the US Department of Energy. Additional support was offered by the National Science Foundation in the United States; nCORE, a wholly owned subsidiary of Semiconductor Research Corporation; the Swedish Research Council; and the Japanese Society for the Promotion of Science.

Journal reference:

Arabchigavkani, N., et al. (2021) Remote mesoscopic signatures of the induced magnetic texture in graphene. Physical examination letters.