Physicists Make a 2-D Magnet
The number of 2D materials has skyrocketed since the discovery of graphene in 2004. However, this collection of semiconductor animals, insulators and superconductors an atom thick lost member magnets. In fact, physicists were not even sure that 2D magnets were possible so far.
Researchers report the first true 2D magnet composed of a compound called chromium tri-iodide, in an article published June 7 in Nature. The discovery could lead to new data storage devices and designs for quantum computers. For now, 2D magnets allow physicists to perform experiments that were previously impossible and test the fundamental theories of magnetism.
Paul Jarillo-Herrero, a condensed matter physicist at the Massachusetts Institute of Technology in Cambridge, and Xiaodong Xu, an optoelectronics researcher at the University of Washington in Seattle, looking for a separate 2D magnet before meeting in 2016. They decided to combine their forces to investigate. “It’s a matter of principle: there are a lot of things missing,” says Jarillo-Herrero.
Xu and Blacksmith Jar-worked with chromium triiodide because it is a glass comprising stacked sheets that can be separated using the “Scotch Tape Method” means a way of making 2D materials using adhesive tape to remove layers each Thinner. Scientists have also been attracted to the compound because of its magnetic properties.
As the magnet, chromium triiodide is one, a ferromagnetic material that generates a magnetic field due to permanent aligned turns of its electrons. Chromium triiodide is anisotropic, which means that its electrons have a preferred direction of rotation – in this case, perpendicular to the plane of the crystal. These fundamental properties made Xu and Jarillo-Herrero suspect that chromium triiodide retain its magnetic properties when they would be stripped in a single layer of atoms. This is something other 2D materials can not do.
Crystals were removed from chromium triiodide and sheets from one or more layers Group Blacksmith-developed Jarillo, while the Xu laboratory studied samples using a sensitive magnetometer.
The team found that not only a single atomic layer of magnetic chromium triiodide, but also that this property has emerged for what is considered a relatively warm temperature: about -228 ° C. Also found a sheet two layers of this material is not Magnetic, but when a third was added, the substance again becomes ferromagnetic. The magnetic material remains if a fourth layer is added, but extended to other properties that researchers say it continues to investigate.
Method in which magnets
Jarillo-Herrero and Xu are not the only ones to study 2D magnets. At the end of April, another group of researchers published their observations of magnetism on an ultrafine crystal of chromium, germanium and tellurium. A 2D magnet retains its magnetism in the layer to be a single atom, although this ultra-thin crystal was only several magnetic layers.
Both results are significant, however, says Nitin Samarth, a condensed matter physicist at Pennsylvania State University at University Park who was not involved in the job. Samarth wrote a commentary accompanying recent studies. Prior to these discoveries, “we never had a generic method for creating 2D magnetic materials actually,” he said. Researchers have tried to manufacture and study ultra-thin magnets since the 1970s, but all of the resulting materials contain holes and bumps and are not really 2D.