Scientists at IBM have figured out how to magnetize single atoms of the rare-earth metal holmium, essentially creating the smallest data storage unit possible.
The downward trend to increasingly compact data storage may have finally reached its limit. Today’s hard drives use about 100,000 atoms to store one bit of data, but if it were possible to stamp individual atoms with 1’s and 0’s, imagine how much more densely packed a data storage device could be.
“Common hard-disk technology achieves a data density of about one terabit per square inch; using single-atom magnets, we could reach a thousand times that density,” says Fabian Natterer, co-author of a new study published in the journal Nature. Natterer and colleagues at IBM Research have achieved the feat by taking advantage of the magnetic spin of atoms found in a state called magnetic bistability.
Researchers were able to place a single atom of the metal holmium, used in powerful magnets, on a magnesium oxide plane and jolt it with electrons, causing the atom to switch its spin state and to retain its state, a first for nanotechnology.
The change in magnetic spin was then “read” by putting a lower voltage charge through the atom and measuring its resistance, thus creating both a way to mark the atom in a binary fashion (like the traditional 1’s and 0’s) and a way to read that information once encoded. The researchers were able to complete the process with two atoms, each independently charged so that they produced four binary combinations (00, 01, 10 and 11).
While the creation of stable atom-sized magnets is remarkable, the process is at this point only temporary, as over time in the lab the magnetized atoms lost their imposed spin, a condition that will need to be worked on if ever the method were to become practicable, says Chris Lutz, nanoscience researcher at IBM and co-author of the new study.
“As the atoms are heated we would expect them to start flipping spontaneously,” said Lutz, to Tech Crunch. “This is because thermal energy being a significant fraction of the energy barrier between the states. Practical memories will need to increase this barrier by use of several atoms coupled together, or by exploring more innovative use of individual atoms.”
The findings have been hailed as a breakthrough. “It’s a landmark achievement,” said Sander Otte, a physicist at Delft University of Technology in the Netherlands to Nature. “Finally, magnetic stability has been demonstrated undeniably in a single atom.”
On the quantum computing front, IBM recently announced that it will launch the its first universal quantum-computing service sometime in the upcoming year. Dubbed the IBM Q, the system which unlike will be available online and purchasable by the public. The cloud service is seen as the next phase after the company’s Quantum Experience cloud computing which debuted last year.
“Having it up for ten months has taught us a lot,” says IBM physicist Jerry Chow, to Nature. IBM’s main competitor in quantum computing, Burnaby, BC, company D-Wave has had a quantum computing service available for use on the cloud since 2010.
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