Single atoms hold on to information

Minutes-long data storage beats previous record of tiny fraction of a second

NANOMAGNETS  Individual magnetic atoms of holmium, seen here as multicolored blobs in a scanning tunneling microscope image, can store information for minutes at a time.

T. Miyamachi/KIT

Individual atoms can store information for minutes at a time, researchers report in the Nov. 14 Nature. That’s more than a billion times as long as any previous experiment with single atoms.

Computer hard drives store data using magnetized cells that each consist of up to a million atoms; the direction of the atoms’ collective magnetization determines whether the cell holds a 1 or 0. Scientists would love to coax individual atoms to store information, but single atoms are unpredictable. For one thing, they continually exchange electrons with their surroundings, causing their magnetization to vary from one moment to the next.

Researchers including Wulf Wulfhekel, a physicist at the Karlsruhe Institute of Technology in Germany, set out to minimize atoms’ interaction. They placed atoms of the element holmium on a platinum surface. Surveying the atoms one by one with a supersensitive microscope, Wulfhekel’s team found that the holmium atoms got wedged between atoms of platinum, making it difficult for holmium to gain or lose electrons. The holmium atoms had consistent magnetic strength and direction for an average of 10 minutes, besting the previous record of 200 billionths of a second.

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