In a first, scientists have discovered that magnetic properties can exist even in the two dimensional (2-D) realm of mono-layers, or materials that are formed by a single atomic layer. The study proved that material chromium tri-chloride has magnetic properties in the mono-layer form, which may open up a world of potential applications possibly in the information technology industry.
"What we have discovered here is an isolated 2D material with intrinsic magnetism, and the magnetism in the system is highly robust," said Xiaodong Xu, Professor at the University of Washington. "We envision that new information technologies may emerge based on these new 2-D magnets," Xu added, in the paper published in the journal Nature. Atoms within mono-layer materials are considered "functionally" two-dimensional because the electrons can only travel within the atomic sheet, like pieces on a chessboard.
To discover the properties of the material in its 2D form, the team used Scotch tape to shave a mono-layer off the larger, three dimensional (3D) crystal form. Surprisingly, in chromium tri-chloride flakes that are two layers thick, an optical signature demonstrating the magnetic nature disappeared. This signature returns in a three layered structure. The scientists will need to conduct further studies to understand why the material displayed these remarkable layer-dependent magnetic phases. But to Xu, these are just some of the truly unique properties revealed by combining mono-layers.
"2D mono-layers alone offer exciting opportunities to study the drastic and precise electrical control of magnetic properties, which has been a challenge to realise using their 3D bulk crystals," Xu mentioned. "But an even greater opportunity can arise when you stack mono-layers with different physical properties together. There, you can get even more exotic phenomena not seen in the mono-layer alone or in the 3D bulk crystal," he said.