A team including Kyoto University researchers said Thursday that it has taken a major step toward the practical use of a light, low-cost and high-performance carbon magnet not requiring rare earth minerals.

High-performance magnets are used in various products such as electric vehicles, smartphones and medical devices.

Among such magnets, those based on neodymium, a rare earth mineral, are widely used. But they are heavy, difficult to process and vulnerable to supply risks.

For these reasons, carbon, which is easy to obtain and is light, is attracting attention as a magnet material.

The team including Kyoto University professor Hiroshi Sakaguchi and assistant professor Takahiro Kojima chose to use graphene nanoribbons, ribbon-like structures made of ultrathin sheets of carbon atoms arranged in a mesh pattern.

It was known from theoretical calculations that making the ends of the ribbon asymmetric would turn it into a magnet, but it was difficult to create such a structure.

The team designed asymmetric carbon molecules that serve as components of graphene nanoribbons and had the components align in certain directions on a metal substrate, succeeding in creating graphene nanoribbons with asymmetric ends.

Through measurements, the team confirmed that the ribbons had the properties of a carbon magnet. But current carbon magnets can maintain their magnetic force only in a vacuum.

"We have to overcome various barriers before putting (carbon magnets) into practical use, including by making them usable in the atmosphere and strengthening their magnetic force," Sakaguchi said.

The team announced the results of its research on the British journal Nature on Thursday.