Scientists induce an artificial ‘magnetic texture’ in graphene

BUFFALO, NY – Graphene is very strong, lightweight, directional … the list of its high quality properties goes on.

It is not, however, magnetic – a shortcoming that has hindered its usefulness in spintronics, an emerging field that scientists say may be rewriting rules. electronic eventually, leading to semiconductors, computers and other more powerful devices.

Now, an international research team led by the University of Buffalo is reporting on progress that could overcome this hurdle.

In a study published today in the journal Corporate Review Letters, researchers describe how they coated a magnet with graphene, and how they inspired what they describe as an “artificial magnetic texture” in the nonmagnetic magnetic material.

“Independently of each other, graphene and spintronics have an incredible ability to fundamentally change many aspects of business and society. But if you can combine the two, the synergistic effects tend to be something unseen. this world remains, ”says lead author Nargess Arabchigavkani, who conducted the research as a PhD candidate at UB and is now a postgraduate research associate at the SUNY Polytechnic Institute.

Additional authors include UB, King Mongkut Ladkrabang Institute of Technology in Thailand, Chiba University in Japan, China University of Science and Technology, Nebraska Omaha University, Nebraska University Lincoln, and Uppsala University in Sweden.

For their experiments, researchers placed a 20-nanometer-thick magnet in direct contact with a sheet of graphene, which is a single layer of carbon atoms arranged in a two-dimensional honeycomb surface of less than 1 nanometer of graphene. thickness.

“To make you aware of the size difference, it’s something like putting a brick on a sheet of paper,” says study lead author Jonathan Bird, PhD, professor and chair of electrical engineering at the School of Engineering and Applied Sciences UB.

Researchers then placed eight electrodes in different locations around the graphene and magnet to measure their conductivity.

The lightning strikes – the magnet stimulated an artificial magnetic texture in the graphene that stood even in areas of the graphene away from the magnet. Simply put, the close communication between the two objects caused the normal non-electromagnetic carbon to behave differently, exhibiting magnetic properties similar to common magnetic materials such as iron or cobalt.

Moreover, it has been found that these properties can completely overwhelm the natural properties of graphene, even when you look several microns away from the contact area of ​​the graphene and the magnet. This distance (a micron is a millionth of a million meters), while very small, is relatively large speaking microscopically.

The findings raise important questions related to the microscopic origins of the magnetic texture in graphene.

More importantly, Bird says, the extent to which the induced magnetic behavior arises from the influence of spin polarization and / or spin-orbit bonding, which is a phenomenon known to be closely related to the magnetic properties of materials and to the technology emerging spintronics.

Instead of using the electric charge that electrons carry (as in traditional electronics), spintronic machines try to make use of a special quantum building of electrons called spin (which seems to be to the ground spinning on its own axis). Spin offers the ability to pack more data into smaller devices, thus increasing the power of semiconductors, quantum computers, large storage devices and other digital electronics.

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The work was supported by funding from the U.S. Department of Energy. Additional support came from the U.S. National Science Foundation; nCORE, a wholly owned subsidiary of Semiconductor Research Corporation; Swedish Research Council; and the Japan Society for the Advancement of Science.