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Crowdyour, you changed the intro section to say:
A consistent theory of cuprate compounds does not currently exist; ... interest in this field is beyond the goal of achieving the room-temperature superconductivity.
This is almost the opposite of what I wrote before. But I must admit that the intro was very unclear before and I took a guess at what the original author was trying to say.
How does high-temp SC compare to room-temp SC? Is one seeing more research than the other? Is room-temp more or less likely to happen?
I assumed that room-temp SC was unlikely, and therefore more research is going into "high" temp SC. But obviously someone who knows needs to clarify.
Also, "the" should not appear before "room-temperature superconductivity". (English)
It is not true that "low temperature superconductors" always needs liquid helium temperatures. Generically, "low temperature superconductors" are defined by not being "high temperature superconductors". This just means that they are described by the conventional BCS theory. For instance, magnesium diboride (MgB2) is the most recently discovered conventional superconductor, and it has a Tc of 35K. The BCS theory describes "phonon mediated" electron pairing. Although it cannot predict Tc, there are general arguments that say that Tc can not get above 30-35K.
Some contemporary hi-Tc theories try to invoke phonons, but there is no consensus on their applicability. The largest peice of evidence against phonons is the lack of "isotope effect", where Tc is proportional to the square root of the mass of the isotopic substitution element occuring at one particular doping level in YBaCuO (optimum doping). The extended BCS theory, which generalizes weak coupling phonons to stronger coupling, known as the Eliashberg theory, predicts that the exponent will not be exactly 1/2, but will be material dependent. —Preceding unsigned comment added by 24.86.198.146 ( talk • contribs) 05:28, 26 November 2004
The current description of work on the subject is very narrow and inaccurate in a number of places. Most notably, the leading theories which are being pursued are not the ones mentioned. A proper treatment both from a historical and Popperian perspective is necessary to achieve credibility. While not an easy task, a balanced approach to describing currently active theories is necessary if the article is to achieve some degree of respectability.
This page should be merged with High-temperature superconductors 220.244.224.10 00:36, 16 Mar 2005 (UTC)
![]() | The contents of the Fermi surface of superconducting cuprates page were merged into High-temperature superconductivity on 22 May 2016. For the contribution history and old versions of the redirected page, please see its history; for the discussion at that location, see its talk page. |
Why it seems like there's no study on this together with the first element? -- Cacumer 18:33, 3 February 2006 (UTC)
I've been out of the field for too long to make good contributions to this article. But "back in the day" I actively avoided the term "high temperature" to describe these materials. Yes, it's high compared to the Tc of Nb3Sn, but 100 Kelvin is not "high" in any absolute sense. What will we call the 200 K superconductors of the future? "Collosal High Temperature"? I propose "perovskite superconductors" or "cuprate superconductors", unless those terms have died out. Spiel496 23:30, 7 April 2006 (UTC)
Maybe we can improve this article by introducing some sections to it. Here's my first cut at a proposal, please feel free to edit / change / add mercilessly:
-- James Slezak 01:15, 21 June 2006 (UTC)
It seems that many of the materials listed are very out of date. Also, no mention of nanotubule research Dtsvaro 08:47, 30 July 2006 (UTC)
It appears that high temperature superconductivity early reports of CNT = carbon nano tubes has not been confirmed. Other types of nano tubes, perhaps. Ccpoodle 17:53, 22 July 2007 (UTC)
I'm commenting these out. I assume they're being used as guidelines for future development, but the article needn't look like a skeleton in the interim. Chris Cunningham 10:49, 22 February 2007 (UTC)
http://news.bbc.co.uk/2/hi/technology/6412057.stm
i think that's interesting and a good source. —The preceding unsigned comment was added by 80.133.226.122 ( talk) 09:57, 6 March 2007 (UTC).
Chapter 'How High-Temperature Superconductors are Made' seems to be very similar to the last chapter 'How does STI make its thin-film microelectronics, or microchips?' on http://www.suptech.com/tech_faq.htm 84.231.69.60 19:01, 28 June 2007 (UTC)
http://www.eetimes.com/news/latest/showArticle.jhtml;jsessionid=HTTOTGYXPCPWSQSNDLSCKHA?articleID=206904213 —Preceding unsigned comment added by 82.131.210.162 ( talk) 11:38, 20 March 2008 (UTC)
At the moment the article is dominated by the original type of HTS. Copper oxide details could move into cuprate superconductors so we can have a more balanced summary of the other families here including fullerenes, MgB2 and now the oxypnictides. Rod57 ( talk) 17:17, 14 June 2008 (UTC)
This is in my opinion not correct. The original article is to my knowledge:
M. K. Wu, J. R. Ashburn, C. J. Torng, P. H. Hor, R. L. Meng, L. Gao, Z. J. Huang, Y. Q. Wang, and C. W. Chu
Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressure
Phys. Rev. Lett. 58, 908 - 910 (1987)
change it? —Preceding unsigned comment added by 141.20.202.78 ( talk) 10:55, 29 June 2008 (UTC)
Comment by rcarden: With all due respect, the discovery was made by the UAHuntsville group who was NOT acting under Chu's direction. They enlisted the Houston group to perform additional magnetic measurements. Chu himself confirms this in “High-Temperature Superconducting Materials: A Decade of Impressive Advancement of Tc” ( http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=614424):
I received an exciting call from M. K. [Wu] at about 5 pm, January 29, 1987. He informed me that he and his students had just observed a reversible R drop above 77K in two of their samples. All of us were ecstatic, since stable superconductivity above 77K might have finally been achieved. M. K. and his student, Jim Ashburn, decided to fly to Houston to carry out a definitive magnetic check with us. Without knowing the elements used in their samples, we tested a few samples, with La replaced by the newly arrived Y and Yb oxides. We failed to detect 90K superconductivity in these samples the night before their arrival. M. K. and Jim arrived late on the morning of January 30, with their samples, which had a nominal formula of (Y0.6Ba0.4)2CuO4 (YBCO). A thorough battery of resistive and magnetic tests (Fig. 4) in various fields showed the R drop M. K. observed to be superconductivity above 90K. Following the recipe of M. K., several more samples were immediately made in Houston and tested the same day. Most showed superconductivity up to 93K. The long sought stable superconductivity above 77K was discovered. — Preceding unsigned comment added by Russellcarden ( talk • contribs) 19:32, 1 December 2011 (UTC)
Whoever inserted that 185K claim link it looks like self-hype by a fringe american company and is probably as real as the milk jar cold fusion (i.e. bullshit). Those guys describe their actions as exactly as a housewife mixing ingredients for a soup... I think it should be removed. 82.131.210.162 ( talk) 18:24, 15 July 2008 (UTC)
This section currently seems confused between the magnetic field - temperature phase diagram that characterizes the ordering of the superconducting vortex lattice, and the transition temperature - chemical doping phase diagram that defines the superconducting properties of cuprates or iron-based materials. These might be better discussed in separate sections. Since the doping phase diagram applies to all cuprates (and separate ones for other types of HTS) it should be the "General phase diagram". The vortex ordering diagram is not universal and applies equally well to layered materials that are not HTS. Figures like those referred to in the external links would also significantly improve this section. 78.86.83.92 ( talk) 23:07, 24 January 2009 (UTC)
Looks like it is just a low volume measurement but it blows away all high temp superconductors in this article. Y3Ba5Cu8O18
http://nextbigfuture.com/2009/10/confirmation-of-ultra-ycbo.html —Preceding unsigned comment added by 99.23.163.109 ( talk) 22:45, 12 October 2009 (UTC)
From article:
Where is the Thallium? Link http://www.nature.com/doifinder/10.1038/365323a0 suggests the compound is HgBa2Ca2Cu3O8+δ. Yet the article Unconventional superconductor claims
Links disagree too, HgBa2Ca2Cu3O8 + δ by Tl substitution, vs. HgBa2Cam-1CumO2m+2+δ (m=1, 2, and 3) .
How about cleaning up by someone knowledgable? --12:07, 15 December 2009 (UTC) —Preceding unsigned comment added by 193.71.38.142 ( talk)
The highest Tc of 138 K is also shared by the fluorinated HgBa2Ca2Cu3O8+δ compound (
http://prb.aps.org/abstract/PRB/v63/i6/e064511) that, under 23 GPa, reaches the highest Tc up to date (january 2010) of 166 K (see Physica C: Superconductivity Volumes 408-410, August 2004, Pages 23-24 and
http://www.iop.org/EJ/abstract/0295-5075/72/3/458) Please, include this info in the article. —Preceding
unsigned comment added by
190.17.214.222 (
talk)
17:16, 14 January 2010 (UTC)
The article mentions "Fermi temperature" but links to Fermi level, an article that does not mention temperature at all. I don't pretend to understand any concept that starts with "Fermi" (I don't understand those articles; they appear written for physicists who already know the subject matter). But a reference that does not explain a technical concept is not acceptable in an encyclopedia. Can someone who understands the subject matter please fix this, or add an understandable definition of Fermi temperature? It would be nice to know the nature of the upper bound for HT superconductor temperatures, with some examples of actual values (of course, any future discovery of room-temperature SC will render my issue moot). David Spector 22:02, 25 February 2010 (UTC)
Recent paper:
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)LeadSongDog come howl! 20:37, 25 March 2011 (UTC)
Why is that? —Preceding unsigned comment added by 168.156.40.253 ( talk) 20:06, 16 May 2011 (UTC)
In previous talk contributions, as well as in the main text of the Wiki article, only published data should be taken as trustworthy that have been verified by at least two independent research groups (and published in refereed journals). A detected and even published "record" high Tc by a single group can have various reasons (wrong interpretation of data, wrong temperature calibration). To my knowledge, neither (Tl5Pb2)Ba2Mg2Cu9O17+ nor Y3Ba5Cu8O18 nor the fluorinated Hg-cuprate nor the Tl containing 138 K "record" superconductor have ever been reproduced in a second independent laboratory. 89.217.204.173 ( talk) 09:23, 27 December 2012 (UTC)
The only 2 mentions of a claim of a 138 K Tc in peer-reviewed research journals are in the 2 papers by the same research group (Sun, Wong, Xi, Lu, and others) in Physics Letters A 192 p. 122 (statement of Tc = 138 K) and in Physica C 243 p. 201 (neutron diffraction results probably on the same samples as reported in the Phys. Lett. A paper). I have not found any other report that has ever reproduced that high Tc in an independent experiment. It is true that books and articles are referring to those publications, but they do not confirm the results by independent research, just citing them. As a researcher, I wonder why there are hundreds of papers by different research groups confirming a Tc of 133-135 K in HgBa2Ca2Cu3O8+δin experiments, but no independent experimental confirmation of the claimed world-record of 138 K in Tl-substituted HgBa2Ca2Cu3O8. It would only be natural for a researcher to immediately jump on this and publish new results. 89.206.116.83 ( talk) 18:21, 2 January 2013 (UTC)
References
Superconductivity on a hot summer day: 29 July 2013 See http://www.superconductors.org/38C_rec.htm The material is Tl5Pb2Ba2SiCu8O16+ and it works at 38°C!
Time to update the article I think! -- Graham Proud ( talk) 13:39, 11 August 2013 (UTC)
I think the page should be updated including the most recent discoveries (the last one on December 2011).
The superconductor (Tl5Pb2)Ba2Mg2Cu9O17+ works at 28°C.
See http://www.superconductors.org/28C_RTSC.htm — Preceding unsigned comment added by 87.5.194.174 ( talk) 19:50, 19 June 2012 (UTC)
Yeah, I don't believe anyone has reproduced this. So it probably is not correct. — Preceding unsigned comment added by 80.229.151.12 ( talk) 15:45, 5 April 2015 (UTC)
I suggested we add a graph to highlight the tremendous progress made in the last 40 years - Tc is just rocketing up! As an example see the graph at this History of Superconductivity page.
Is there a way to automate this somehow in Wikipedia, like an RSS feed or something? For example, "The highest critical temperature achieved to date is XXX in YYYY material". -- Graham Proud ( talk) 03:06, 18 August 2013 (UTC)
OK, I concede about the automation thing! I always was a gadget geek! However I think it would be worthwhile verifying Joe Eck's claims. -- Graham Proud ( talk) 11:03, 26 August 2013 (UTC) Thanks SPat, I reworded the discovery sentence to emphasis multiple sources.-- Graham Proud ( talk) 01:19, 10 January 2014 (UTC)
To my knowledge, Iron-Aresinide superconductors discovered around 2008 are considered high Tc superconductors as well. This needs to be reflected in the article. — Preceding unsigned comment added by Condmatstrel ( talk • contribs) 16:49, 30 August 2013 (UTC)
In case it's later shown to be backed up by experiments:
On 2013-10-08 theoretical physicists calculated and predicted the electronic properties of a topological insulators, which conduct electricity only on the edge or surfaces. It consist of a single layer of tin and fluorine atoms which could be the first material to conduct electricity with 100% efficiency at computer chip temperatures. Experiments to confirm the finding is under way in November 2013. [1] [2] [3] Electron9 ( talk) 11:56, 26 November 2013 (UTC)
References
a single layer of tin atoms — could be the world's first material to conduct electricity with 100 percent efficiency at the temperatures that computer chips operate
Upon consulting unbiased Phd's in the subject it seems that the following null hypothesis is correct.
The materials on super*****.* are NOT in fact superconducting, the phenomenon discovered is giant magnetoresistance highly dependent on temperature.
1) No independent replications of even a hint of HTSC above 164K 2) The materials show such a small resistance change that even if they did work they would be virtually useless at even cryogenic temperatures. 3) No (as in zero) improvement since early 2002 when even Y123 was reformulated within a year. 4) Not even a hint of any commercial product(s) 5) Not even a mention of these "miracle materials" in any other peer reviewed scientific journal. 6) No evidence of even a simple levitation experiment which would show genuine superconductivity. 7) Every single condensed matter researcher spoken to feels 1-6 are likely accurate.
Self publishing is often a bad sign in the scientific community, by all means include preliminary results but the more outlandish the claim the more likely it is to be wrong. Case in point, Henrik Schon fooled many people with his plastic "superconductor" but was later caught out when his results were not reproducible and graphs were found to be fabrications. — Preceding unsigned comment added by 185.16.70.246 ( talk) 02:32, 21 October 2014 (UTC)
The history section presently states: "In the late 1970s, superconductivity was observed in certain metal oxides at temperatures as high as 13 K (−260.1 °C), which were much higher than those for elemental metals." I guess that this is wrong. The "popular" superconductors known in the 70s with Tc higher than that of elemental Nb were compounds like NbN, NbTi, Nb3Sn or Nb3Ge, i.e. not oxides.-- HBook ( talk) 20:09, 14 March 2015 (UTC)
I suggest someone should add a section on properties of HTCs which limit their applications and usefulness: the fact that they do not form large continuous superconducting domains but only clusters of microdomains within which local superconductivity occurs, and therefore are useless for applications requiring actual superconducting currents (such as superconducting magnets for magnetic resonance); and, the fact that being ceramics rather than metals, HTCs are brittle and not malleable and cannot easily be shaped or molded. HandsomeMrToad ( talk) 07:15, 2 October 2015 (UTC)
Dear colleagues,
In the "
Examples" section, the table's header includes the text: "(Boiling point of liquid nitrogen for comparison)".
I understand the importance of the boiling point of liquid nitrogen in this topic; however, the table also includes rows for the boiling points of: liquid helium, liquid hydrogen, liquid oxygen, plus two other reference temperatures. Also, the use of the word "comparison" is a bit puzzling, since the boiling points are supplied essentially as referential indicators.
Would the table header therefore not be clearer if the text in parentheses read: "(Various boiling points shown for reference)"?
I hope the above suggestion will be received in the positive light in which it was made.
With kind regards;
Patrick. ツ
Pdebee.
(talk)(
guestbook)
17:33, 28 March 2016 (UTC)
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Hi, according to [1] LaH10 superconducts at 250+ K at 150 GPa. Should this also be added, for completeness? — Preceding unsigned comment added by 185.3.100.40 ( talk) 06:21, 5 July 2019 (UTC)
References
The development of commercial yttrium barium copper oxide ribbon supercondutors has led to the growing use of the term "REBCO tape" to describe them in shorthand, as a quick websearch will reveal. This article is lacking mention of this term, which appears to be gaining usage rapidly. Some addition in this regard is needed to keep this article relevant to current discussion (to show up in websearches, for one thing). 2001:56A:F0E9:9B00:55E9:D0B5:54A7:B271 ( talk) 04:17, 17 April 2020 (UTC)justsomewikireader
Our definition was at "temperatures above nearly 73.15 K", which is patently silly, and not supported by the ref used. Is there a precise def? Above the triple point of N2, perhaps? Or its boiling temp at 1 atm? I put both figures in w citation-needed tags. — kwami ( talk) 11:33, 19 September 2020 (UTC)
There seems to be more about cuprate superconductors on this page than on the actual Cuprate superconductor page. I wonder if this page would be more effective if it focused more on giving a broad overview, and left many of the specifics to the separate article on cuprate superconductors (which could certainly be expanded, including much information from this page)-- Mittens10 ( talk) 18:26, 19 January 2021 (UTC)
Analysis: why HTSC theory is still not in creation (means, conceptually: still far away from being formulated logically) — Preceding unsigned comment added by 90.242.248.189 ( talk) 09:22, 7 December 2021 (UTC)
Shouldn't TS be more appropriate? Even TSC?
Every conductor conducts (C)at a high temperature (T). JohndanR ( talk) 16:00, 19 January 2024 (UTC)