Using scan-tunneling microscopy, researchers were able to separate the atom's spin and orbital rotation. Artist rendition of the atom studied under the needle of a tunnel microscope. (Image credit: TU Delft)


Researchers at the Delft University of Technology recently made a discovery that could bring a huge change to how information is stored in atoms. The team successfully manipulated two different types of magnetism within a single atom. These results are essential to developing extremely small forms of data storage.


The magnetism of an atom occurs from electrons orbiting around the nucleus of the atom. The rotations are broken up into two categories: rotation around the nucleus of the atom, known as orbital angular momentum and the rotation of the electron around its own axis called spin angular momentum, or spin. In theory, each of these rotations could be used to store information, but in practice, it's quite challenging to achieve. Researchers note if the orbital direction is reversed, the spin direction changes with it and vice versa.


Researchers were able to reverse the direction without changing the spin direction due to a phenomenon first predicted by Einstein and Johannes de Haas. According to this effect, reversing the orbital direction can be compensated by a small rotation of the environment, which in this case would be the piece of metal that belongs to the atom. Previously, the effect had not been studied on the scale of a single atom.


So how exactly did researchers achieve the manipulation? The team used scan tunneling microscopy, where a sharp needle scans atoms and moves them at will. To separate the spin and orbital rotation, they positioned a magnetic iron atom on top of a single, non-magnetic nitrogen atom. By doing this, they created an ideal geometry that rarely occurs naturally.


Storing information in individual atoms could increase the current maximum storage capacity by many thousands of times. But useful atomic storage won't be possible for a long while. Still, this discovery is a step in the right direction.


"The main result is that we have taken another step forward in our ability to control atoms and even the electrons that orbit around them," said research leader Sander Otte. "That is a wonderful goal in and of itself."


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