A Billion-Year Hard Drive

Never forget. Microscopic iron crystals moving within carbon nanotubes could hold computer data permanently.

Zettl Research Group/LBNL/UC Berkeley

That embarrassing home movie of you naked in the tub could still be around millions of years from now, along with your less-than-eloquent posts on Facebook and Twitter. Researchers have developed a new technology based on carbon nanotubes that promises to permanently preserve individual bits of data, such as those found on computer hard drives and DVDs. If so, the technology could lead to data archives holding the entirety of human thought and communications potentially forever.

As our technological society has progressed, storing and retrieving data has actually grown more difficult. One notable example is the Domesday Book, a record of English settlements compiled by William the Conqueror in 1085. The document survives in a secure, environmentally controlled facility, but a digitized version produced in 1986 lasted only 20 years: Magnetic patterns embedded in the computer disk degraded steadily over time. Likewise, home movies shot on Kodachrome film have preserved family memories for more than 60 years, whereas videotapes can deteriorate in less than a decade. And some DVDs have shown signs of image loss even more quickly, because their plastic and glue layers have turned out to be relatively fragile and are vulnerable to sunlight exposure and mishandling--a phenomenon called DVD rot.

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Back and forth. Watch a nanoparticle move in a carbon nanotube.
Courtesy Zettl Research Group, Lawrence Berkeley National Laboratory and University of California, Berkeley

Seeking something more permanent, a team of physicists and materials scientists has looked to the nanoscale. Reporting this month in Nano Letters, the group describes a technique of placing a single iron crystal only a few billionths of a meter wide inside a hollow carbon nanotube. Like diamonds, nanotubes are among the most stable structures in existence. Once inserted into the tubes, the iron nanocrystals act as data bits, physically sliding from one end of the tube to the other in response to an electric current and in the process registering either a "1" or a "0" in the binary language of computers. "Nothing could be easier, electronically speaking," says physicist and co-author Alex Zettl of the University of California, Berkeley.

Zettl says the technology will require further tests, but results from both lab experiments and theoretical models show with "high confidence" that the device can retain data indefinitely. He says commercialization of the device--which would probably look something like a flash drive--will be challenging, "going up against a mature electronics memory industry." But given the potential impact, he says, the incentives are high.

Materials engineer Mark Spearing of the University of Southampton in the United Kingdom calls the study "well conducted" and the technology "ingenious." Nothing is permanent, though, he says. Such a device could fail for any number of reasons, says Spearing, some of which may be currently unknown.

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