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nanotimes News in Brief

10-09 :: September 2010

Information Storage // IBM Scientists Have Measured How Long Information Can Stay in an Individual Atom

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BM (NYSE: IBM) researchers published a technique that measures how long a single atom can hold in-

formation, and giving scientists the ability to record, study and “visualize” extremely fast phenomena inside these atoms.

“This technique developed by the IBM Research team is a very important new capability for characte- rizing small structures and understanding what is happening at fast time scales,” said Michael Crom- mie, University of California, Berkeley. “I am parti- cularly excited by the possibility of generalizing it to other systems, such as photovoltaics, where a com- bination of high spatial and time resolution will help us to better understand various nanoscale processes important for solar energy, including light absorption and separation of charge.”

In the experiment, iron atoms were deposited onto an insulating layer only one atom thick and sup- ported on a copper crystal. This surface was selected to allow the atoms to be probed electrically while retaining their magnetism. The iron atoms were then positioned with atomic precision next to non-magne- tic copper atoms in order to control the interaction of the iron with the local environment of nearby atoms. The resulting structures were then measured in the presence of different magnetic fields to reveal

that the speed at which they change their magnetic orientation depends sensitively on the magnetic field. This showed that the atoms relax by means of quan- tum mechanical tunneling of the atom’s magnetic moment, an intriguing process by which the atom’s magnetism can reverse its direction without passing through intermediate orientations. This knowledge may allow scientists to engineer the magnetic lifetime of the atoms to make them longer (to retain their ma- gnetic state) or shorter (to switch to a new magnetic state) as needed to create future spintronic devices.

“This breakthrough allows us – for the first time – to understand how long information can be stored in an individual atom. Beyond this, the technique has great potential because it is applicable to many types of physics happening on the nanoscale,” said Sebastian Loth, IBM Research.

Sebastian Loth, Markus Etzkorn, Christopher P. Lutz, D. M. Eigler, Andreas J. Heinrich: Measurement of Fast Electron Spin Relaxation Times with Atomic Resolution, In: Science, Vol. 329(2010), No. 5999, September 24, 2010, Pages 1628-1630, DOI: 10.1126/science.1191688: http://dx.doi.org/10.1126/science.1191688

http://www.youtube.com/watch?v=DmTeKpOrVNw