Researchers develop magnetic cloak using standard materials

The ‘magnetic cloak’ could be used to protect implanted medical devices such as pacemakers and cochlear implants — although it might also potentially be used surreptitiously to hide metallic weapons from security portals.

Previous attempts at creating cloaking technology have focused on developing entirely new metamaterials that have underlying properties not found in normal matter.

‘Metamaterials are very costly to manufacture since they are often complex, fine-tuned structures,’ Prof Àlvar Sánchez of the Autonomous University of Barcelona (UAB) told The Engineer. ‘The challenge we posed ourselves was to design a cloak that yielded complete, not reduced, invisibility and made from commercially available materials.’

Their device is a cylinder built using a high-temperature superconductor material, easily refrigerated with liquid nitrogen and covered in a layer of iron, nickel and chrome.

‘To come up with the final engineering-like solution, we needed to work a lot with the physics and mathematics of transformation optics,’ Sánchez said.

The superconductor layer of the cylinder prevents the magnetic field from reaching the interior, but distorts the external field and thus makes it detectable.