bit created with only 12 atoms. IBM researchers reported that achievement in obtaining the smallest magnetic
yet on Thursday, potentially leading to an entirely new class of nanomaterials for computers.
Previously, even advanced magnetic storage required about a million atoms to indicate a digital 0 or 1. Up to this point, the company said, it had not been clear what the smallest number of atoms needed to create a single magnetic memory bit was. IBM said in a statement that the research pointed toward magnetic storage that is "at least 100 times denser than today's hard disk drives and solid state memory chips."
96 Atoms Store 'Think'
The research findings were reported in the current issue of the journal Science, and could result in lower powered magnetic storage and new arenas for quantum computing. The researchers used the 12-atom bits to create an array of 96 atoms that stored the word "think," IBM's motto.
The research has been stimulated by an international competition between the Institute of Applied Physics at the University of Hamburg, Germany, and IBM's Almaden Research Center in San Jose, Calif. The German institute announced last spring that it had been able to conduct logic operations with atoms, and now IBM has developed the smallest unit of magnetic storage -- six iron atoms in each of two rows, on a surface of copper nitrite.
The atoms in the IBM research are antiferromagnetic, in which each atom in the array has an opposite magnetic orientation, unlike regular materials like iron or nickel, where the magnetic orientation is lined up. A major issue with extremely small magnetic data storage in regular materials is the magnetic interaction of neighboring atoms with one another. The antiferromagnetism allowed the team to pack the atoms more closely than was previously possible.
One catch to the new accomplishment -- it was obtained at a temperature close to absolute zero, which certainly limits its practicality. But the research team said that a similar effect can be accomplished at standard room temperature, with as little as 150 atoms.
The way in which this feat was accomplished also limits its replicability. Researchers employed scanning tunneling microscopes to position individual atoms. But other research teams are now investigating new ways to manufacture materials with storage at this atomic level, using either mechanical or biological techniques.
At the atomic level of a relatively few number of atoms, quantum effects begin to kick in, so that, for instance, the "bit" can be both 0 and 1 simultaneously. Andreas Heinrich, the IBM team leader, told The New York Times that this quantum effect, which could advance the new technology of fantastically powerful quantum computers, is a major part of the research's value.
"If you step outside of the press release," he told The New York Times, "we are trying to control the quantum mechanics of this spin behavior to coax them to do whatever we want them to do."