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Science

Surprising Superconduction in Plutonium 49

Posted by michael from the million-and-one-uses dept.
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."
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Surprising Superconduction in Plutonium More

Surprising Superconduction in Plutonium

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  • Pb--Great (Score:3, Insightful)

    by Henry V .009 ( 518000 ) on Friday December 06, 2002 @12:47PM (#4827331) Journal
    Superconducting power lines would transmit electricity from power plants to homes without most of the energy loss that occurs now

    Unless someone takes them down to build an atomic bomb!
    • Superconducting power lines would transmit electricity from power plants to homes without most of the energy loss that occurs now

      ...unless the temperature ever goes above freezing... for DRY ICE.

      • > Superconducting power lines would transmit electricity from power plants to homes without most of the energy loss that occurs now
        >
        >...unless the temperature ever goes above freezing... for DRY ICE.

        So 90% of Canada is safe. At least, it sure feels that way. *G*

      • Re:Pb--Great (Score:1)

        by Anonymous Coward
        Nope, sorry to be nitpicky, but dry ice freezes around -70 to -80 degrees celcius, by comparison, 18 deg. K = -255 deg. C

    • Re:Pb--Great (Score:3, Informative)

      by capnjack41 ( 560306 )
      I don't think that's the point. I think they're just interested on what impact this has on superconductor theory. No one's about to build a huge radioactive train or a bunch of radioactive power lines.

      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.

      • IANANP either, so someone please explain just what "depleted uranium" is. If it's depleted, then it isn't uranium anymore, is it?

        Also, depleted uranium isn't plutonium, so it's probably not superconducting. Sorry.

        • I think it's just uranium with fewer neutrons shootin' out than before. I'm pretty sure it's still uranium atoms though, just not radioactive (do they break down into other elements? someone knows). I think that's what it is, IANANP, AFAIK, IIRC...

        • Re:Pb--Great (Score:3, Informative)

          by mindstrm ( 20013 )
          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.;

        • IANANP either, so someone please explain just what "depleted uranium" is. If it's depleted, then it isn't uranium anymore, is it?

          It refers to the amount of the isotope with atomic weight 235. "Natural" uranium is mostly the 238 isotope, with (IIRC) about .07% of 235.

          "Enriched" uranium has a higher ratio of U235, and "depleted" has a lower ratio. Weapons and some power plant designs require enriched uranium because it has different fission characteristics (e.g. the probability that a neutron will cause the nucleus to split).

          Enriched, natural, and depleted uranium are chemically the same; plutonium is different.

    • Re:Pb--Great (Score:1, Informative)

      by crossconnects ( 140996 )
      Pb -- lead Pu -- plutonium

  • "OK, lets freeze this plutonium, (Score:4, Funny)

    by Unknown Poltroon ( 31628 ) <unknown_poltroon1sp@myahoo.com> on Friday December 06, 2002 @12:49PM (#4827343)
    and run high voltage through it"

    Dosent this sound like some kind of bad b-move plot?? Im wating for the time traveling DeLorean to show up.
  • We used to have these breakthroughs in superconductivity some months ago. But I thought they were gone.

    Are you sure this wasn't discovered by Jan Hendrik Schon [wired.com]?

  • I thought the best superconductors would
    work at close the temperature of salty
    ice water, say -15C or 258K. 18K is like
    -255C. That's pretty damn cold.

    • Re:18K relatively warm? (Score:5, Informative)

      by jerde ( 23294 ) on Friday December 06, 2002 @02:09PM (#4827968) Journal
      Right. Okay. Go read the article [spacedaily.com]! (This is the correct response to 90% of the posts in this thread)

      18K is relatively warm compared to plain-old superconducting metals. When superconductivity was discovered in 1911 [superconductors.org] 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.org] 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:
      The discovery has no immediate practical value but is important because it adds a new dimension to the study of superconductivity, Stewart said.

      "You can't make practical materials out of something as radioactive and chemically poisonous as plutonium," he said, "but John Sarrao and this collaborative team have made a big leap in understanding superconductivity from a fundamental point of view."


      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
      • All very interesting. I remember a huge debate here on /. a while ago where the big question was about the speed of electricity vs. the speed of light, and how the speed of electricity was normally only 2/3 that of light. Does this also hold true in superconductors? Or can they transmit electricity faster? Just curious.

        • Re:18K relatively warm? (Score:2, Informative)

          by jerde ( 23294 )
          According to this site [starkelectronic.com], 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 [amasci.com], 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 [google.com], but I found a message board posting [cornell.edu] that states that the electron drift rate is much higher in superconductors.

          And then there's this physics Q&A [sciencenet.org.uk] about why electrons don't travel at actually the speed of light.

          - Peter

  • WHAT?! (Score:3, Funny)

    by Hubert_Shrump ( 256081 ) <cobranet@g[ ]l.com ['mai' in gap]> on Friday December 06, 2002 @01:16PM (#4827576) Journal
    You mean we were fitting rockets to those things for years, when all we needed was a great huge magnet?

    Man, the Pentagon's going to be pissed.

  • That's a very low temperature. If I remember correctly, there are ceramic composites that become superconducting at temperatures far over 100 K.
  • 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) [amsuper.com] 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.

  • 18K is pretty warm given the circumstances.. (Score:3, Interesting)

    by Tyrnagog ( 609616 ) on Friday December 06, 2002 @01:49PM (#4827801)
    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.

    While Plutonium is "extremely radioactive and chemically toxic", it is just a base metal, not a compound. I am not to familiar with the metallic properties of Plutonium (malleability, brittleness, etc) but I would imagine that if one metal (even if it is trans-uranic) has high K properties like Plutonium, others may as well...
    • Plutonium's metallurgy is very strange. One of Richard Rhode's books (about the making of the fission and fusion bombs) mentions that it has something like five different states around STP. Its mechanical properties are, to my understanding, annoying. In other words, even aside from the radioactivity and toxicity, you still don't want to make anything about it.
    • 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.
    • how do you cool anything that far???

  • more info (Score:1, Offtopic)

    by raduga ( 216742 )
    More detail [google.com] from the expert.

    At long last, maybe Archimedes Plutonium [google.com] will get the attention [killfile.org] he deserves for his brilliant theories explaining how the entire universe is really a single atom of plutonium.

    001 A picture introduction to the ONE ATOM PLUTONIUM EVERYTHING UNIVERSE, 231PU ATOM TOTALITY theory [newphys.se]

    Excerpt follows:

    Note that the start of this website is the Atom Totality theory and the end of this website is sci.religion which is apt, for think of the website rankings not as linear but as a circle coming back around. So we start with the hard core most general of all sciences and the most easily verified of all sciences-- physics and like a circle we come around to the worship of physics in sci.religion. Below in chemistry I have a circular periodic table, so think of the rankings on this website as sci.physics at the top and coming full circle back around is sci.religion which is basically the worship of physics since God is 231Pu and the best bible is the best most up-to-date physics textbook.

    • Somebody should get this guy together with the TimeCube [timecube.com] guy.
    • I just read this first page (Introduction to 231Pu universe etc [newphys.se]) and it is the biggest load of crap I've seen since creationism. I'm surprised the Swedish government allows the association of its TLD with this junk.

      Why do I say this? I read the page, and see this guy making his claims. Where's his evidence? I scroll down some more waiting for the exposition to end and the science to start. Hmm, still none, still just more guff saying how clever the guy thinks he is. Whoops, it's the bottom of the page. Perhaps he should rename his site 'tabloidphysics.se'.

      And the actual source material: He didn't actually say what his theory was, but I glark that he thinks the universe is an atom of plutonium, and the Milky Way is one of its electrons. Now, riddle me this. The universe has more than 94 galaxies. So, unless I've just busted his theory, I guess I haven't read far enough to reach the section where he rubbishes observational astronomy?
      • For those less usenet-travelled, Archimedes Plutonium is one of the great net.kook wackos of all time. His countless insufferable posts to the physics and science groups, have long since driven all but Kibo [kibo.com] to distraction.

        And anyway, considering his post I linked to was actually ON the subject of "the superconductivity of plutonium", I find it hard to see how the post would be moderated offtopic.

        Troll, sure, but that's not what I got.

  • Can anyone actually point me to a useful working product of superconductors, or holograms or nanotechnology ? Apparently, these things are the Holy Grail of Science. Methinks they are more like the Emperor's New Clothes.
    • 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.
      • 1. OK, are these things really using semiconductors in production units? If so, good!
        2. Actually in a commercial product?
        3. forgot about the holos on money. Ok, besides that! :) Still, not a whole lot of examples here. Wish it weren't true, but it is. Cheers, :})||
        • 1 it would be impossible to get those kinds of intense magnetic fields without using superconductors. Conventional conductors would melt with the kind of electrical current you would need.

          2 unfortunately buckyballs don't seem to lubricate. [sciencenet.org.uk] but see that post on FLIR [slashdot.org] made with nanotechnology for more commercial nanotech products.

          3 You want great 3d uses of holograms? Try imaging [caltech.edu] This technique could generalise for anything else you want to look at under a microscope in 3D. Cells. Fuel rods in a nuke reactor. the hologram captures all that data at the quantum level.

          the application is commercial because there are hologram companies that sell equipment to other companies. If you want to get into it yourself for next to nothing look at this link [repairfaq.org] and search for hologram [drexel.edu]

  • Type I vs. Type II Superconductor (Score:3, Insightful)

    by DrLudicrous ( 607375 ) on Friday December 06, 2002 @11:38PM (#4830743) Homepage
    I am by far no expert in superconductivity, but I have worked with superconductive materials here and there. This discovery seems very similar to that of MgB2, which superconducts at about twice the temp, 37K or so. If I remember correctly, wasn't that a type-I superconductor? It seems to me that this plutonium-based superconductor (is it just pure Pu?) would be a classical BCS type-I superconductor. Most type-II's tend to be really complex as far as their constiutent elements numbers and ratios, e.g. YBCO. Plus, 18K is well below 37K, so in the regime of classical type-I Tc's. Also, I think that the cooper pairs are probably being formed by the valence f-orbital electrons. Maybe a theorist can show that this yields the lowest possible ground state energy. Besides, Yb of YBCO fame is also in the same group of elements as Pu who have partially filled f-orbitals.

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