At small scales, tug-of-war between electrons can lead to magnetism.

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By CHARLOTTE HSU
Published: July 7, 2011

 At the smallest scales, magnetism may not work quite the way scientists expected, according to a recent paper in Physical Review Letters by Rafal Oszwaldowski and Igor Zutic of UB and Andre Petukhov of the South Dakota School of Mines and Technology.

The three physicists have proposed that it would be possible to create a quantum dot—a kind of nanoparticle—that is magnetic under surprising circumstances.

Magnetism is determined by a property all electrons possess: spin. Individual spins are akin to tiny bar magnets, which have north and south poles. Electrons can have an “up” or “down” spin, and a material is magnetic when most of its electrons have the same spin.

Mobile electrons can act as “magnetic messengers,” using their own spin to align the spins of nearby atoms. If two mobile electrons with opposite spins are in an area, conventional wisdom says their influences should cancel out, leaving a material without magnetic properties.

(Click to read more)

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