Iron filings in a magnetic field

Magnetic fields move iron filings — but have no effect on objects wrapped in a magnetic ‘cloak’. Credit: Windell Oskay/CC BY 2.0

Materials science

Cloak conceals contents from magnetic ‘eyes’

Device is not dependent on supercooling to foil magnetic fields.

Scientists have developed a magnetic ‘invisibility cloak’ that functions at room temperature.

Devices that shield objects from detection by magnetic fields have been developed before. But such cloaks tend to rely on superconducting magnets, which are unwieldy and require extremely low temperatures. Wei Jiang, Yungui Ma and Sailing He at Zhejiang University in Hangzhou, China, formed a cylinder from a highly magnetic material and ran copper wires up and down the cylinder’s length. When current passes through the wires, the device mimics the properties of a superconductor — shielding the space inside the cylinder from magnetic influence and detection.

Devices with this capability could be useful in medical scans, and for hiding metallic objects for military purposes, the authors write.