'Antimagnet' Cloak Hides Objects From Magnetic Fields

ananyo writes "Researchers have made a cloak that can hide objects from static magnetic fields, realizing a theoretical prediction they made last year. This 'antimagnet' could have medical applications, but could also be used to subvert airport security. The cloak's interior is lined with turns of tape made from a high-temperature superconductor. Superconductors repel magnetic fields, so any magnetic field enclosed within a superconductor would be undetectable from outside. But the superconductor itself would still perturb an external magnetic field, so the researchers coated its external side with an ordinary ferromagnet. The superconductor tries to repel external field lines, whereas the ferromagnet tries to draw them in — together, the two layers cancel each other out (abstract)."

Re:MRI

[Anonymous Coward]

It renders the object invisible to static magnetic fields. MRI utilizes rapidly changing magnetic fields to encode position. This is still a problem.

High temperature superconductor, misleading

[mark-t]

Because it's not "high temperature" in any sense that would be understood by the term.

It's called high temperature because it's significantly hotter than temperatures where superconductivity occurs in ordinary metals (around 30K). But even the highest temperature at which superconductivity has ever been observed is still freakin' cold... over a hundred degrees below 0

Until room temperature superconductivity is discovered (an enormous breakthrough in physics that would have countless applications), nothing's getting by airport security with this mechanism.

Re:High temperature superconductor, misleading

[Anonymous Coward]

Nice way to take a comment out of context. OP stated:

nothing's getting by airport security with this mechanism

Not, 'nothing's getting by airport security'. (bolding mine)

Take something out of context and suddenly it has vastly different meaning. You probably already knew this, and were seeking a cheap upmod.

Re:This solves what? New?

[50000BTU_barbecue]

I was about to mention mumetal, but its claim to fame is very high permeability. It doesn't repel magnetic fields, it Shamwows them. I suppose if the mumetal is saturated from the inside, then it doesn't hide the object from an external field. Although it takes a lot to saturate properly treated mumetal.

Old man story time. My Tektronix 547 CRT oscilloscope has its CRT encased in a mumetal shield. I got a powerful magnet and put it on the side of the case, the trace didn't budge at all. Great stuff. Of course, mumetal loses its properites if it's dinged, deformed or otherwise mechanically abused.