IBM has figured out how to store data on a single atom

Researchers from IBM and the Swiss Federal Institute of Technology (EPFL) have managed to create a new type of data-storing mechanism, that uses individual atoms as bits.

As memory devices are becoming increasingly smaller, it was hypothesized whether the elementary storage unit could one day be as small as a single atom. IBM will continue to research with "atoms of other elements, clusters of atoms, and small molecules as candidate magnetic bits", one of the researchers told TechCrunch. However, despite tremendous research efforts, the magnetization of single atoms was never stable enough due to spontaneous fluctuations.

Holmium is known to possess magnetic behavior.

Given that all magnets have two poles, their orientation can be used to determine whether an atom is a 0 or a 1.

The single-atom, read-write storage system is arranged by placing atoms on a substrate of magnesium oxide that acts as an insulating layer between the metal electrodes beneath it and the magnetic atoms on top of it. Given that modern hard drives need about 100,000 atoms to store a single bit, this development could shrink the size of future storage mediums by an order of magnitude.

IBM says the researchers used a single iron atom to measure the magnetic field of the holmium atoms-turning it to measure what states the holmium atoms were in, like a tiny compass-and a scanning tunneling microscope, a powerful microscope developed by IBM (which won its inventors Gerd Binnig and Heinrich Rohrer the Nobel Prize for physics in 1986) to image the surface of individual atoms. To read the state of the holmium bits, the scientists relied on a phenomenon called "tunnel magnetoresistance", which enabled them to see the direction of the Ho atom's magnetization.

The study was published today in the peer-reviewed journal, Nature. It verifies that the read/writes of the Ho atom are a lasting stored magnetic state but it is only there for experimental purposes. In tests they could reliably write and read back four possible states with each atom's magnetism being changed independently (00,01,10,11). But when will this happen?

"To demonstrate independent reading and writing, we built an atomic-scale structure with two Holmium bits, to which we write the four possible states and which we read out both magneto-resistively and remotely by electron spin resonance", claim the researchers in their paper.

  • Carolyn Briggs