An electromagnetic shield: http://iopscience.iop.org/1367-2630/13/9/093034/fulltext
"In summary, we have presented a method to design hybrid superconductor–metamaterial devices that prevent any magnetic interaction with its interior while keeping the external magnetic field unaffected. Two important key ideas have been needed for achieving our goal: the design of a simplified cloak with homogeneous parameters, corresponding to a new space transformation, and the placement of a superconducting layer at the inner surface. Such an antimagnet would be passive and, provided that the superconductors are in the Meissner state [8] and that the isotropic layers have a negligible coercivity (as if using superparamagnetic materials), also lossless. " <end excerpt>
