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"exec" writes:

Physicists demonstrate the first single-atom magnetic storage.

Current commercial bits comprise around 1 million atoms. But in experiments physicists have radically shrunk the number of atoms needed to store 1 bit — moving from 12 atoms in 2012 to now just one. Natterer and his team used atoms of holmium, a rare-earth metal, sitting on a sheet of magnesium oxide, at a temperature below 5 kelvin.

Holmium is particularly suitable for single-atom storage because it has many unpaired electrons that create a strong magnetic field, and they sit in an orbit close to the atom's centre where they are shielded from the environment. This gives holmium both a large and stable field, says Natterer. But the shielding has a drawback: it makes the holmium notoriously difficult to interact with. And until now, many physicists doubted whether it was possible to reliably determine the atom's state.

To write the data onto a single holmium atom, the team used a pulse of electric current from the magnetized tip of scanning tunnelling microscope, which could flip the orientation of the atom's field between a 0 or 1. In tests the magnets proved stable, each retaining their data for several hours, with the team never seeing one flip unintentionally. They used the same microscope to read out the bit — with different flows of current revealing the atom's magnetic state.

-- submitted from IRC

[Ed's note: removed the reference/footnote that was mangling the year - FP]

Original Submission