Researchers claim atomic-level storage
More electron spin?
By Chris Mellor | Techworld | Published: 16:20, 03 April 2007
Scientists have demonstrated single bit data storage at the atomic level. This could, it is claimed, open the way to nanoscale memory a hundred times denser than today's flash and RAM, possibly more.
The effect was reported by scientists Andrei Sokolov and Bernard Doudin writing in the Nature Nanotechnology journal. It depends upon so-called spin electronics, spintronics for short.
This is an area of quantum physics in which the electrons flowing through nanoscale metallic wires have their spin affected by the magnetic state of the atoms in the wire though which they are flowing. The phenomenon is called ballistic anisotropic magneto-resistance (BAMR) and is a cousin to that used by giant magneto-resistive (GMR) read heads in modern disk drives.
With BAMR the electrons' spin can be either positive or negative and varies in a readily detectable way. The two spin states can represent a binary one or zero and are detected by variations in the resistance of the wire.
Spintronic memory was demonstrated with a one atom-wide cobalt wire laid down on a silicon substrate. BAMR storage would be built up from individual bit-level cells composed of nanoscale wires with the capability of being magnetised. Sensors would be needed for each cell to detect the direction of spin.
It could not be used for disk or tape-type storage because their recording media is even and consistent, not being made up from fabricated cells. With individual BAMR cells being nanoscale, the prospect is of memory a hundred or even a thousand times more dense than today's flash or RAM.
Dr Charles Barnes, chairman of Dataslide, said: "This fundamentally addresses capacity. ... Given that some of the basic work was done several years ago and that there are so many competing technologies especially in media, I think that it will be very much a case of it being taken up by a hardware company, and at the moment probe storage seems to be the flavour of the times. I heard at a conference recently that several hundred millions of dollars are being expended in this area, i.e. IBM Millipede and beyond."
Dr Simon Carrington of the Farfield Group said: "It looks like it would work.... The relative capacity looks high. It's difficult (at this early stage) to comment on its potential for commercialisation. The timescale? Five years minimum is a pretty good guess."
Other nanoscale memory technology developments include a nanowire grid work. Carrington said:" This (nanotechnology memory) field is changing day by day. Who knows what it will look like in five year's time?"