The thinnest materials in the world are only a single atom thick. These kinds of two-dimensional or 2D materials—such as graphene, well-known as consisting of a single layer of carbon atoms—are causing a great deal of excitement among research teams worldwide. This is because these materials promise unusual properties that cannot be obtained using three-dimensional materials. As a result, 2D materials are opening the door to new applications in fields such as information and display technology, as well as for critical components in extremely sensitive sensors.
Structures known as van-der-Waals monolayers are arousing particular interest. These are combinations of two or more layers of different materials that are each only a single atom thick, with the layers held to one another by weak electrostatic van-der-Waals forces. By selecting the type and sequence of material layers bound in this way, specific electrical, magnetic, and optical characteristics can be chosen and modified. However, scaled-up homogeneous deposition of individual van-der-Waals layers having ferromagnetic properties has not yet been achieved. Yet it is precisely this kind of magnetism on a larger scale that is particularly important for several potential applications—such as for a novel form of non-volatile memory for example.
Scientists from the Max Planck Institute for Microstructure Physics in Halle, Germany, the ALBA synchrotron light source in Barcelona, Spain, and the Helmholtz-Zentrum Berlin have now succeeded for the first time in creating a uniform two-dimensional material—and demonstrating an exotic ferromagnetic behavior within it known as "easy-plane" magnetism.
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