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Archive for September 24th, 2010

IBM Improves Its Nanotechnique

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IBM researchers have published a breakthrough technique in the peer-reviewed journal Science that measures how long a single atom can hold information, and giving scientists the ability to record, study, and “visualize” extremely fast phenomena inside these atoms.

The scientists at IBM Research in our Almaden Labs are using the Scanning Tunneling Microscope like a high-speed camera to record the behavior of individual atoms at a speed of about one million times faster than previously possible.

IBM researchers in Zurich invented the Scanning Tunneling Microscope in 1981 and were awarded the Nobel Prize for their efforts.

Since then, IBM scientists have been pushing the boundaries of science using the Scanning Tunneling Microscope to understand the fundamental properties of matter at the atomic scale, with vast potential for game-changing innovation in information storage and computation.

The ability to measure nanosecond-fast phenomena opens a new realm of experiments for scientists, since they can now add the dimension of time to experiments in which extremely fast changes occur.

To put this into perspective, the difference between one nanosecond and one second is about the same comparison as one second to 30 years. An immense amount of physics happens during that time that scientists previously could not see.

In addition to allowing scientists to better understand the nanoscale phenomena in solar cells, this breakthrough could be used to study areas such as quantum computing, which are radically different types of computers not bound to the binary nature of traditional computers but which instead have the potential to perform advanced computations that are not possible today.

Or information storage technology, which, as technology approaches the atomic scale, provides scientists the opportunity to explore beyond the limits of magnetic storage. This breakthrough specifically allows scientists to “see” an atom’s electronic and magnetic properties and explore whether or not information can be reliably stored on a single atom.

Hold On: This Gets Geeky

Since the magnetic spin of an atom changes too fast to measure directly using previously available Scanning Tunneling Microscope  techniques, time-dependent behavior is recorded stroboscopically, in a manner similar to the techniques first used in creating motion pictures, or like in time lapse photography today.

Using a “pump-probe” measurement technique, a fast voltage pulse (the pump pulse) excites the atom and a subsequent weaker voltage pulse (the probe pulse) then measures the orientation of the atom’s magnetism at a certain time after excitation. In essence, the time delay between the pump and the probe sets the frame time of each measurement.

This delay is then varied step-by-step and the average magnetic motion is recorded in small time increments.  For each time increment, the scientists repeat the alternating voltage pulses about 100,000 times, which takes less than one second.

In the experiment, iron atoms were deposited onto an insulating layer only one atom thick and supported 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-magnetic 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 quantum 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 magnetic 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, about the discovery. “IBM’s continued investment in exploratory and fundamental science allows us to explore the great potential of nanotechnology for the future of the IT industry.”

A Majorly Small Matter

Among IBM’s many nanotechnology milestones, its scientists won a Nobel Prize for inventing the Scanning Tunneling Microscope, devised methods to manipulate individual atoms for the first time – famously spelling the letters IBM with 35 Xenon atoms – developed logic circuits using carbon nanotubes, and incorporated sub-nanometer material layers into commercially mass-produced hard disk drive recording heads and magnetic disk coatings.

IBM’s current nanotechnology research aims to devise new atomic- and molecular-scale structures and methods for enhancing information technologies, as well as discovering and understanding their scientific foundations.

To learn more about this latest breakthrough, check out the following YouTube video (which includes some nanotech animations and interviews with our humans who explain the new technique).

You can also check out some pics from this technique here on Flickr.

Just don’t forget: It’s a small world after all.

Written by turbotodd

September 24, 2010 at 10:24 pm

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