The First Antimagnet
September 23, 2011 Leave a comment
From ScienceDaily: researchers design a means of shielding an object from external magnetic fields and preventing internal magnetic fields from escaping; if implemented, it seems like this would be a pretty big find.
Spanish researchers have designed what they believe to be a new type of magnetic cloak, which shields objects from external magnetic fields, while at the same time preventing any magnetic internal fields from leaking outside, making the cloak undetectable…
The antimagnet has been designed to consist of several layers. The inner layer would consist of a superconducting material that would function to stop a magnetic field from leaking outside of the cloak, which would be very useful to cloak certain metals.
A downside to using this material, however, is that it would distort an external magnetic field placed over the cloak, making it detectable, so the device would need to be combined with several outer layers of metamaterials, which have varying levels of magnetic field permeability, to correct this distortion and leave the magnetic field undisturbed.
I might as well give you wikipedia’s description of metamaterials, since they sound awesome:
Metamaterials are artificial materials engineered to have properties that may not be found in nature. Metamaterials usually gain their properties from structure rather than composition, using small inhomogeneities to create effective macroscopic behavior.
The primary research in metamaterials investigates materials with negative refractive index. Negative refractive index materials appear to permit the creation of superlenses which can have a spatial resolution below that of the wavelength. In other work, a form of ‘invisibility’ has been demonstrated at least over a narrow wave band with gradient-index materials. Although the first metamaterials were electromagnetic, acoustic and seismic metamaterials are also areas of active research.
So metamaterials are being studied as a means of shielding an object from visible light, and not letting visible light escape from it; this “antimagnet” application is analogous, but presumably uses metamaterials designed for a different aspect of the electromagnetic field. In fact it’s been reported as an “invisibility cloak” in some places, but it seems that the researchers themselves prefer the term antimagnet.
You would think something like this would come with fantastical proposed applications, but to my dismay it did not; the most prominent one was to shield people’s implants and pacemakers so that they could use MRI machines. Really? That’s great, but these writers did not have their sci-fi thinking caps on. What does this mean for the (distant) future of metal detectors, for example? And as with many discoveries, I trust that smart people will come up with entirely unexpected and phenomenal applications.
All that being said, I must note that they didn’t actually make an antimagnet, they just designed a theoretical one, although they insist that it’d be relatively easy to make with materials currently available. We’ll see if it goes through.