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Surprising Superconduction in Plutonium
jihema writes "Dr Strangelove would have liked this : a plutonium compound turns out to be a superconductor at relatively high temperature (18 K). The magnetic properties of this metal make this fact rather unexpected and contradicts the accepted theory on superconduction."
The article clearly says the team was at Los Alamos National Laboratory. LANL has the authority for this type of work. Sarrao is not some random university professor. He works for LANL.
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18 K is hardly a "low-temperature" superconductor. That temperature is around where helium finally becomes a liquid, which was where superconductor research was at the turn of the 19th to the 20th century. Nowadays, we have things like HTS material (bismuth-based, copper oxide ceramic) which will superconduct up to temperatures of 108 K! A far cry from 18 K.
For those metric impaired people in the audience, 108 K (aka -165 C) is -265 F. 18 K (aka -255 C) is - 427 F. HST composites only need liqud nitrogen (which costs the same as milk), rather then liquid helium (which is very, very, very expensive) to work.
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18K is relatively warm compared to plain-old superconducting metals. When superconductivity was discovered in 1911 occurring in Mercury, later in other metals as well, it was at only a few degrees Kelvin. 18K is relatively warm compared to that.
Half a century later, in 1986, we found ceramic compounds that would superconduct at much much higher temperatures. Those compounds superconduct by a different process, so they're dubbed Type 2 superconductors. (as opposed to Type 1 for metalic elements)
The article doesn't say -- or they probably don't even know for sure -- what type of superconductivity was observed in Plutonium. Or if they were using pure elemental Plutonium or some compound that contained it.
And finally, lots of other comments here make fun of how "useful" Plutonium is. Duh. It's not:
Basically, it means that superconductivity is still not completely understood -- this uncovers yet another twist, and will help to develop the theories further.
Secrets of the universe stuff, you know.
- Peter
INsigNIFICANT
This makes me wonder. I don't think the article really clarified on whether it was the radioactive property that makes it interesting, or just how the actual metal atom works. If that's the case, then what's the problem with depleted uranium? IANANP (nuke physicist), but I guess since they didn't mention it, it wouldn't work.
Read the article, it talked about superconductors at 138K...however, for materials you 'don't expect' to superconduct, they typically do superconduct, but at around 2-3K.
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superconductors: MRI and SQUID (superconducting quantum interference) medical imaging.
nanotech: buckyballs - best lubricant out there, being composed of billions of nanoscopic ball shaped molecules. Potentially superstrong carbon structures, drug delivery systems, etc. nanotech is still in its infancy.
holograms: used to protect currency all over the world from forgery.
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IT's a differnet isotope of uranium, and it's still radioactive, just not in the right way. IT's relatively safe, you can handle it, etcetera....
but when it gets blown to powder and ends up in the food/water supply, it's not good.
It's probably also highly toxic.
One of the major dangers of plutonium other than radioactivity is the fact that it is extremely toxic.;
Pb -- lead Pu -- plutonium
no big sig
According to this site, the "velocity of propagation" of signals in the blue pair in CAT5 cable is 66% that of "c", the true speed of light. (A few percent of that is because of the twists -- if you completely straightened out the individual wires, they'd stretch longer than the original length of the cable)
Of course there's the difference between the speed of one electron vs. the speed that voltage changes (i.e. information) travel along the wire.
According to this guy, the actual movement of electrons is VERY very slow through a normal wire, on the order of centimeters per hour.
What about superconductors?
I didn't have tons of luck Googling, but I found a message board posting that states that the electron drift rate is much higher in superconductors.
And then there's this physics Q&A about why electrons don't travel at actually the speed of light.
- Peter
INsigNIFICANT
All of the very high K superconductors (>100 K) are (IIRC) brittle ceramic compunds that could not be easily constructed into something of commercial use.
Nope. They are easily constructed into something of commercial use. I work on the technology. It is just not cheaper than copper wire for power transmission (yet). Superconducting cables are, however, currently used in various specialized applications, and in 2004, a superconducting power transmission cable will be installed in the Northeast US. The Japanese and Germans are making great advances as well as the US. Although the superconductors are "brittle" ceramics, one can wind a superconducting cable around a bottle neck, and it will still work fine. Why? It's thin. If that doesn't explain it, consult basic mechanics of materials textbook.