Researchers have shown that it is possible to study the magnetic properties of ultrathin materials directly, via a new nano microscope that opens the door to the discovery of more two-dimensional (2D) magnetic materials, with all sorts of potential applications. The findings are significant because current techniques used to characterize normal (three-dimensional) magnets don’t work on 2D materials such as graphene due to their extremely small size – a few atoms thick.
So far there has been no way to tell exactly how strongly magnetic a 2D material was. To address the problem, the team employed a widefield nitrogen-vacancy microscope, a tool they recently developed that has the necessary sensitivity and spatial resolution to measure the strength of 2D material. The technique works by bringing tiny magnetic sensors extremely close to the 2D material in order to sense its magnetic field.
To test the technique, the scientists chose to study vanadium triiodide (VI3) as large 3D chunks of VI3 were already known to be strongly magnetic. Using their special nano microscope, they have now shown that 2D sheets of VI3 are also magnetic but about twice as weak as in the 3D form. 2D magnetic materials are expected to play a key role in future energy-efficient electronics.