Talk:Superconductivity

I would like to see some information on the nuclear resonnance properties of type II superconductors. If electromagnetic radiation is applied to the superconductor at its main resonnance frequency will the radiation be deflected or absorbed? --cacapitol

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Somewhere we need to mention the specific temperatures for some superconductors - and note that high temperature is not high in normal life. Probably need to use Celsius, not Kelvin scale for general readers. --rmhermen

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I have re-written the article so that the distinction between conventional superconductors and unconventional superconductors is made clear. This is important, because although the field of unconventional superconductivity (including high-temperature superconductors) is very ebullient, conventional superconductivity on the other hand is a very well-established subfield of solid-tate physics (and particularly BCS theory is a fully-working theory, if you apply it to conventional superconductors). But the article seemed to have more about unconventional superconductors than conventional ones, which is odd. I have not deleted that material, but moved it to new articles (unconventional superconductors, high-temperature superconductors, technological applications of superconductivity). Hope this is all right.

By the way, I think keeping the Kelvin is all right, since it is the natural unit in superconductivity. It is important to have links to its definition, though. --quintanilla

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I'm a bit in doubt about the first line. I'm not sure superconductivity is a "state of matter", but a characteristic of certain elements and substances in given conditions.

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We know that superconductivity is not a property of metals, but a thermodynamic state of matter different from the metallic state, because of the Meissner effect. The argument is quite standard: a perfect metal (i.e. one with zero resistivity) would support resistanceless flow of an electric current and expel magnetic fields from its interior, just like a superconductor, but if at high temperatures, when the resistivity is finite, a magnetic field is applied, and then the temperature is lowered, the perfect metal does not expel the field, while the superconductor does. In contrast superconductivity is really a thermodynamic state which is characterised by zero field inside the sample however you got there (applying field first, cooling down afterwards, or the other way around). I know this is very sketchy. When I have time I will write it more carefully in the articler about the Meissner effect. Or if you have more time than me maybe you can look it up in "Superconductivity", J.B. Ketterson and S.N. Song, Cambridge University Press 1999, Section 1 - Introduction (pages 1 and 2) or in any other textbook on Superconductivity (e.g. the one by Tinkham, or the one by Schrieffer). Since this argument usually appears in the introduction of such textbooks, it is usually written in a way that is relatively easy to understand. Ciao, jqt

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Why change "External links" to "Web resources"? The former is more common in wikipedia? Tiles 08:06, 29 Jul 2003 (UTC)

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I'm very curious what energies have been achieved in superconductors, as a novice. I have heard rumours that superconductors have potential applications as energy storage devices. --dikaiopolis

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Currently it says Superconductivity was discovered in 1911 by Onnes. This is somewhat disputed and it is more diplomatic to write Onnes was awarded the Nobel Prize for discovering superconductivity in 1911. I have not rewritten it yet, awaiting more comments before doing so.

Any references? -- CYD

This is known within the superconductivity research community, which is where I picked it up. As with much dirty linen it is not washed in public, thus the rewrite proposal that Onnes got the Nobel prize for it in 1913 (which is undisputed) for the discovery made in 1911 (which is where the controversy lies). A number of Nobel Prize laureates have turned out to be under some controversy. Very, very little of this can be found on the net, one example is the omission of Bell for discovering pulsars. You could make a Wikipedia entry for this alone, that is if you wanted the mother of all edit wars; there is a lot of prestige at stake. Thus I propose Onnes was awarded the Nobel Prize in 1913 for the discovery of superconductivity in 1911.

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Tesla / Superconductor myths

I deleted reference to Tesla. The patent mentions the well known fact that resistance increases with temperature. The patent talks about reducing the resistance by cooling, but no mention of zero resistance. He discusses metallic conductors and liquid air cooling. Even today, there is no metallic conductor which is superconducting in liquid air. pstudier 23:05, 2005 Jan 24 (UTC)

The patent mentioned is:

• Tesla, Nikola, 685,012 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=685012.WKU.&OS=PN/685012&RS=PN/685012), "Means for Increasing the Intensity of Electrical Oscillations". 1900 March 21. USPTO.

pstudier 23:13, 2005 Jan 24 (UTC)

See classications @ http://www.uspto.gov/go/classification/ of US patent 685,012. The patent current U.S. Class is classified as :

Class 327 MISCELLANEOUS ACTIVE ELECTRICAL NONLINEAR DEVICES, CIRCUITS, AND SYSTEMS

527 Superconductive (e.g., cryogenic, etc.) device

Class 505 SUPERCONDUCTOR TECHNOLOGY: APPARATUS, MATERIAL, PROCESS

888 Refrigeration

870 Power supply, regulation, or energy storage system : Including transformer or inductor

856 Electrical transmission or interconnection system

This is besides the mention of the recent US patent citation of US4869598.

Does it matter how the patent office classifies the patent? It should be important. Does wikipedia just deny the facts? I hope not. This patnet does describe the process that would result in superconductivity.

Sign your edits! I have read that whole patent and NOWHERE included in it does Tesla mention any phenomena which describe anything other than the already widely known effect of ordinary reduction of resistivity with the lowering of temperature. It does NOT describe the observation of any superconductive phenomenon. Who cares if the clueless patent officer doesn't know the difference between mere cryogenic conditions and those of superconductivity! Jeez who knew there were so many fawning hyper-obsessive Tesla fanboys here. STOP ADDING this inconsequential, unrelated, nothing edit to the article!--Deglr6328 18:58, 12 Mar 2005 (UTC)

Deglr6328, "Fanboy" that is not NPOV!

The patent office classifies the patent as superconductivity tech (that is important). The patent suggests superconductivity.

The process patented is to increase the ability to keep current (as Onnes himself verified in 1912).

It does describe "zero resistance" .. read the patent, Page 2, lines 50 - 85.

The theory necessary for superconductivity was established by Dewar and Flemming. Tesla understood this and was using Linde's machines [the same thing that Onnes himself used and modified]. Tesla had best equipped lab in the world (from the vast amount of money he made from Westinghouse; and he had many wealthy financiers backing him).

Tesla achieving this, not in secret (read his notes written in colorado springs), with prior knowledge on super-cooling (he had a physics degree and was widely known in europe and america by the best scientists (note who is in his quotation section)). The theory of superconductivity was established nearly a decade earlier than Onnes (again, Dewar and Flemming set forward the notion!).

The superconductor is not an oscillator, but the particular winding of the coil sets up the oscillations. (But you'd have to understand coils (like the bifilar that Tesla invented), each have a specific resonance and frequency, to grasp that!)

The above Page 2, lines 50 - 85 is about operation of the apparatus. You can read the following to get a better idea: Page 1, lines 25 to 39 (best results method). Page 1, 62 to 78 (previous experiments, discovery of circuit to vibrate freely). Page 1, 79 to 83 ("extraordinary degree magnified and prolonged"). Page 2, 3 to 12 (agents used and how-to construct). There is alos the claims, the fifth one is interesting to this discussion

Also read the discussion at Talk:List of Tesla patents. Same Tesla nonsense going on there also. pstudier 19:15, 2005 Mar 12 (UTC)

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Is this true? Additionally, melanin is an organic, polymeric superconductor currently in use in bio-tech research as a possible replacement for gallium arsenide and silicon in high-tech devices -- most notably in nanotechnology and plastic electronics applications. What is its critical temperature? 69.225.131.186 00:53, 6 Feb 2005 (UTC)

You're right. The three edits by Deeceevoice were vandalism. I have reverted them. Thank you for catching that. RJFJR 01:48, Feb 6, 2005 (UTC)

(The prior statement that the edits were vandalism may have been unnecessarily strong; however, the contention that melanin is a superconductor is not supported by mainstream science and does not belong in this article. RJFJR 02:11, Feb 6, 2005 (UTC) )

I do not engage in vandalism. I have reinserted the passage -- but placed it in a previous paragraph that refers to unconventional superconductors. Please don't speak/write on matters about which you know nothing. Use your computer's search engine and investigate before making groundless charges. No one can know everything. [I believe the winners of the 2000(?) Nobel Prize in science were engaged in this kind of research.] There are numerous biotech companies currently engaged in melanin research. What is with you folks, anyway? If melanin were ketchup (or any other organic substance) and not associated with black folks, and if I were not black, would you have been so quick to assume "vandalism"? Very telling. Ya better take a couple of steps back and check yourselves.deeceevoice 03:43, 6 Feb 2005 (UTC)

OK, not knowing anything about that, I'm leaving that alone, but I cut out the link to black supremacy because the connection between superconductivity and black supremacy is really tenuous. - furrykef (Talk at me) 04:34, 6 Feb 2005 (UTC)

No, melanin is not a superconductor. Curiously enough, when I used "my computer's search engine", I came up with this (http://www.csicop.org/si/9201/minority.html). -- CYD

I'm not finding any claims that melanin is a superconductor except in reference to claims of black supremacists... if it really were a superconductor I don't think people would be hush-hush about it (because, quite frankly, I don't think that would provide any real benefit anyway... and Hell, we already know that extra melanin is good to have because it prevents sunburn and skin disease, so it's not like we're keeping benefits of melanin a secret). - furrykef (Talk at me) 04:50, 6 Feb 2005 (UTC)

Go to http://nobelprize.org and search on melanin. The only mention's are in the medicine prizes and concern its biological role. The 2003 physics prize was about superconductivity theory with no mention of melanin. The 2000 chemistry prize was for conductive polymers, no mention of either superconductivity or melanin. Can anyone cite any evidence for melanin being either a conductor or a superconductor? pstudier 05:49, 2005 Feb 6 (UTC)

My profoundest apologies. My edits to Superconductor were the result of an inexplicable cognitive trip (of the really stupid sort that people often make while typing and composing at the same time). The Melanin Theory holds that melanin is a superconductor, when it is widely known to be a semiconductor. This is commonly known in the scientific community (even in its more mundane areas of application such as dermatology and cosmetics with regard to sunburn/melanoma prevention) -- which is why, in reading your comments about my edits, I took such exception to your reactions. I simply didn't understand them.) In editing Black supremacy, I thought to mention the subject of MT and so included it. I explained that MT holds that melanin is a superconductor, but when I went on to explain its recognized physical properties, I inadvertently continued to use "superconductor," when I intended to switch to the appropriate "semiconductor" in its stead. I will allow the reverts of my edits to superconductor because they certainly were not what I intended. I have also made the appropriate changes in related articles, with an added "erroneously" in Black supremacy, where this all started, to emphasize the difference between "superconductor" and "semiconductor."

Come to think of it, I will have to see if black supremacist theory actually recognizes the difference -- that melanin is, in fact, a semiconductor; and if the notion of it being a superconductor is just a misnomer and a distortion of information by the ill-informed that occurred over time. If so, I'll have to go back and correct that, as well. deeceevoice 11:44, 6 Feb 2005 (UTC)

I've added a lot of information to melanin regarding its properties as a semiconductor. You may want to visit and read up. (I think if you were familiar with this subject, you might have caught my earlier slip. Sorry -- again.) The 2000 Nobel Prize in Chemistry was, indeed, awarded to three scientists involved in research into melanin as a polymeric semiconductor. deeceevoice 13:19, 7 Feb 2005 (UTC)

And, FYI, the earliest research (with which I'm familiar, at least) on the semiconductivity of melanin was published in 1974. The related Melanin Theory has been around since about that time and brought this knowledge of the scientific research to members of the African American community 30 years ago. deeceevoice 15:37, 7 Feb 2005 (UTC)