Hot on the trails of the mysterious monopole

[n2doc]

16:30 04 September 2009 by Michael Brooks

We have moved one step closer to finding the mysterious monopole – a magnetic pole without its opposite, which has long eluded physicists. Two laboratory experiments using strange stuff called spin ice have provided the best evidence yet that monopoles really are out there.

Nearly 80 years ago, physicist Paul Dirac said it must be possible to separate the north and south poles of a magnet to give them a separate existence. But despite decades of searching moon dust, the debris from particle collisions and cosmic radiation for traces of a monopole, not one has been found.

Spin ice is a kind of crystalline material with essentially the same atomic arrangements as water ice. Last year, researchers demonstrated that certain states of spin ice would create monopoles that rove about the crystal. The monopoles would be seen as disturbances moving through the spins of atoms within the crystal.

Now two separate groups claim to have seen just that.

more:

http://www.newscientist.com/article/dn17740-hot-on-the-trails-of-the-mysterious-monopole.html