Magnetic media has been the mainstay of computer storage for decades. Just as with processors, shrinking feature size—smaller clusters of magnetic atoms—have allowed huge gains in storage density. Just as with processors, though, these gains are starting to push up against physical limits, as it's getting harder and harder to set the magnetic state of a cluster of atoms without wiping out the information on the neighboring clusters.
Now, researchers at IBM have teamed up with collaborators in Germany and Switzerland to store information using a related phenomenon, antiferromagnetism. And they've shown that it's possible to store a bit in a feature that contains as few as six iron atoms. The downside is that the storage was only stable at extremely low temperatures. If the sample was allowed to heat up to 5K, the information on the bits vanished.