They're not true magnetic monopoles. If I understand correctly, they're unusual crystal structures that approximate the behavior of a monopole in some ways, but

They're not true magnetic monopoles. If I understand correctly, they're unusual crystal structures that approximate the behavior of a monopole in some ways, but they aren't true monopoles. Div(B) still equals zero. Here's an article I found from a month ago that explains spin ice better than the OP: http://blogs.discovermagazine.com/80beats/2009/09/10/physicists-after-the-elusive-magnetic-monopole-spot-a-look-alike/ http://blogs.discovermagazine.com/80beats/2009/09/10/physici...