March 12, 2009
‘Spin battery’ uses new source of energy
U.S. and Japanese physicists say they have demonstrated proof of principle of the existence of a 'spin battery' that's about the diameter of a human hair.
Researchers at the University of Miami and the Universities of Tokyo and Tohoku in Japan said the battery is
charged by applying a large magnetic field to nano-magnets in a device called a magnetic tunnel junction.
We had anticipated the effect, but the device produced a voltage over a hundred times too big and for tens of minutes, rather than for milliseconds as we had expected, said University of Miami Physics Professor Stewart Barnes.
That this was counterintuitive is what lead to our theoretical understanding of what was really going on.
He said the achievement advances science's understanding of the way magnets work.
The study is to appear in an upcoming issue of the journal Nature and is available ahead of print at the publication's Web site.