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Putting a new spin on silicon

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8:15pm, February 8, 2005
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At the heart of data-reading heads in new computer hard drives are devices whose exquisite sensitivity derives from manipulations of a magnetic property of electrons called spin.

Such devices, part of an ascendant technology known as spintronics (SN: 7/5/03, p.14: Available to subscribers at Magnetic current flows solo), might capture more turf from conventional electronics if spintronics developers could somehow render silicon magnetic, says Vincent P. LaBella of the State University of New York in Albany. Now, he and his colleagues may have done just that.

In the Jan. 15 Physical Review B, LaBella's team reports shooting ions of manganese, a magnetic metal, into silicon. As a result, the semiconductor attained a magnetic field about a millionth as strong as the one iron has, LaBella estimates.

That may seem minuscule, but "it's strong enough . . . to be useful for spintronic devices," LaBella says. What's more, the field persisted at temperatures commonly reached in electronic devices.

Some doubts remain about the new material's ultimate usefulness. For instance, tiny clumps, possibly of manganese, form in the bombarded silicon, LaBella says. Such structural irregularities often spell bad news in microelectronic devices.

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