What is Superconductivity: Definition and 143 Discussions

Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered even down to near absolute zero, a superconductor has a characteristic critical temperature below which the resistance drops abruptly to zero. An electric current through a loop of superconducting wire can persist indefinitely with no power source.The superconductivity phenomenon was discovered in 1911 by Dutch physicist Heike Kamerlingh Onnes. Like ferromagnetism and atomic spectral lines, superconductivity is a phenomenon which can only be explained by quantum mechanics. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor during its transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics.
In 1986, it was discovered that some cuprate-perovskite ceramic materials have a critical temperature above 90 K (−183 °C). Such a high transition temperature is theoretically impossible for a conventional superconductor, leading the materials to be termed high-temperature superconductors. The cheaply available coolant liquid nitrogen boils at 77 K, and thus the existence of superconductivity at higher temperatures than this facilitates many experiments and applications that are less practical at lower temperatures.

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  1. K

    Superconductivity in the Presence of a Magnetic Field

    Curious: say, it takes a particular piece of superconductive material "x" seconds to reach the state when submerged in liquid nitrogen. Now, say we try to do the same in presence of a (strong) magnetic field. Does x increase, decrease or does it stay the same? My money is on increasing, because...
  2. S

    What are the latest research topics in materials science and nanotechnology?

    Hi, name's Sehaj. I'm in my first year of a Natural Sciences degree studying at the University of Leeds, England. It's a flexible degree with a masters option which I'm looking to take, perhaps gearing towards working in materials science. But I also have an interest in nanotechnology...
  3. O

    Superconductivity Research ideas

    Hello, I have to do a little research for school. My partner and I liked the topic Supercondutivity. Do you guys know any interesting research topics in this area? We are 16 years old and have basic Physical knowledge. There is an university in our area where we can do research at (if we have a...
  4. D

    Why isn't there any friction in magnet trains?

    Hi there, first poster here. Something has been boggling me and I cannot seem to find the answer anywhere. I really hope that you will help me =) A magnet train in vacuum has no friction whatsoever, right? Then what about electron interactions between the 'rail' and the train itself due to...
  5. A

    Hi everyone :-) Is there any superconductivistist physicist? ;-)

    I just wanted to introduce myself and tell you that my passion and interest is superconductivity and low temperature physics. If there is anyone in this field whether he or she works on experimental aspect or theoretical or computational, or just interested in this field, please let us know!
  6. N

    A question on superconductivity

    Let us suppose that there is a superconducting toroid. Let us also suppose that there is a finite electric current flowing in it. We imagine the temperature of the toroid to be below the critical temperature. Now if we try to raise the temperature of the toroid then due to the law of...
  7. beowulf.geata

    Quinn and Ittner's (1963) superconductivity experiment

    Homework Statement The problem is Exercise 1 here: http://www.open.edu/openlearn/science-maths-technology/engineering-and-technology/engineering/superconductivity/content-section-2.1. I am interested in question (c), where you are asked to estimate the maximum possible resistivity...
  8. V

    Superconductivity and magnetism

    Certain objects are able to influence the behavior of magnets when super-cooled. Does this violate Maxwells equations?
  9. P

    What can be seen if taking a snap shot @ 4.21K? Superconductivity

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  10. C

    D-wave superconductivity: Functional forms?

    Two questions, really: I’m finding it hard to wrap my head around the connections between k-space and real-space for d-wave symmetry, as well as the connections between “order parameter,” “gap,” “Cooper pair wave function,” and “superconducting wavefunction,” which are all mentioned at various...
  11. J

    Superconductivity and zero resistance

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  12. A

    Questions about superconductivity

    Hi 1) Can all chemical elements be superconductive? 2) It is said that in diamagnetic materials there are no unpaired electrons. Does this mean that only such materials can be superconductive?
  13. K

    Is my background too weak to study superconductivity?

    Hi everyone, I tried to study BCS theory but got stuck, here are my notes: I have a civil engineering degree but now I am doing a master course in physics. I know most of the undergraduate level physics including modern physics (base on Young and Freedman's book), although I cannot say...
  14. K

    Is BCS low-temp superconductivity completely accepted?

    is the BCS theory of low temperature superconductivity completely accepted already? any doubters here? I encountered this paper that suggests the BCS is incomplete: http://physics.ucsd.edu/~jorge/abstracts/bcs.pdf "The most quoted reason given as convincing proof that BCS-electron-phonon...
  15. I

    Superconductivity for other forces

    Hi, not sure if this is the right forum but I was wondering if superconductivity could theoretically be accomplished somehow with the weak and strong forces and gravity just as it could be accomplished in the electromagnetic field. Would superconductivity of the strong force be the same as cold...
  16. Z

    How Does Superconductivity Allow for 0 Resistance?

    Superconductivity... awkward Superconductivity says that below certain temperature, certain materials offer 0 resistance to the current flowing through them... But how is this possible ? resistance offered is because of loss of kinetic energy of electrons due to collision with atoms' nuclei...
  17. A

    Why is there zero resistivity in superconductors when there is non-zero entropy?

    According to theory of superconductivity, resistivity almost zero. Below critical temperature the entropy decreases markedly with cooling . why resistivity zero when entropy not equal to zero? my doubt is when there is an entropy there is a disorder. then how can move conducting electron...
  18. N

    Schools Best Universities for Superconductivity Research

    please let me know the best universities for everything about low temperature superconductivity research
  19. M

    Why does superconductivity occur?

    I can't get a definitive explanation of why superconductivity happens and I am getting mixed explanations from my textbooks. I will tell you what I know and hopefully you can correct any misunderstandings I have: • A metal consists of an ionic lattice because the electrons in the valence band...
  20. S

    Theory questions on superconductivity

    Hi just completed a chapter on Superconductivity in a solid-state physics book. I have a few remaining questions. I don't expect they can be easily answered, but I appreciate if someone happens to know. Most of the questions regard how the equations have been motivated. I guess that's kind of...
  21. ShreyasR

    Doubts about basics of superconductivity.

    I am just introduced to basics of superconductivity in Engineering Physics. My lecturer asked a question: Is the resistance of a superconductor zero or close to zero? And my answer was close to zero. I have read that the resistance of a superconductor is exactly zero, but then when I put some...
  22. M

    BCS Superconductivity Development and Controversy

    [Moderator's Note: This thread is split from a textbook thread: https://www.physicsforums.com/showthread.php?p=4275234#post4275234] Exellent book. Especially 1953 year edition. It has no subsequent ideas of Cooper pairing, preventing us of from understanding of HTS...
  23. A

    Any recommendations for a beginner's guide to superconductivity?

    Hi all, Can someone recommend a good book on how to learn about superconductors, a general overview of the field? Is there any book in the field of superconductivity ananlogous to the big book of gravitation in general relativity? If you know of more than one good intro to superconductivity...
  24. N

    Which Field of Theoretical Physics Involves Research in Superconductivity?

    What field in theoretical physics can you enter to do research in superconductivity?
  25. X

    Superconductivity and the BCS Theory

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  26. V

    Are superconductivity and melting not understood?

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  27. S

    Superconductivity by quantum tunneling?

    We have some material with metal atoms inserted in substrate.Maybe by dopping. Electric current is able to move only be quantum tunneling jumping from atom to atom. Could we obtain superconductor in this way?
  28. M

    Would someone explain me superconductivity?

    Would someone explain me superconductivity IN ATOMIC WORLD? if this doesn't belong in quantum physics I am sorry admin
  29. S

    Exploring the Stripe Phase in Superconductivity

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  30. T

    Self inductance and superconductivity?

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  31. R

    Can High Temperature Superconductivity Reach Room Temperature?

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  32. C

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  33. L

    What's the Next Step After Superconductivity: A Very Short Introduction?

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  34. C

    Does superconductivity really have zero resistance?

    Take for instance putting the large hadron collider in space at a near absolute zero where you never have to put energy into cool down the system. The LHC takes 10 GJ to run and the total energy of the two beams is 724 MJ. [1] Since the power to run the system never experiances resistence, would...
  35. T

    Literature Request: Introduction to d-wave superconductivity

    I'm looking for a pedagogic introduction to d-wave superconductivity on the level of field theory. Ideally, this would involve a derivation of d-wave superconductivity and the form of the gap parameter from some fundamental Hamiltonian (if such a derivation is even possible yet). Books and...
  36. R

    High Temperature Superconductivity

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  37. K

    Superconductivity in fullerenes

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  38. S

    Superconductivity and Fermi levels

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  39. Demystifier

    Are Feynman's Equations on Superconductivity Valid?

    In the last chapter of "Feynman Lectures on Physics" part III, Feynman discusses superconductivity. I am particularly intrigued by his equations (21.19) and (21.31), and even more by (21.38). Is there any experimental evidence for validity of these equations? The question of validity of these...
  40. U

    On Solder and Superconductivity

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  41. haael

    Superconductivity and Pauli exclusion principle

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  42. K

    Superconductivity and electron pair

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  43. D

    Collective modes and restoration of gauge invariance in superconductivity

    After the first explanation of superconductivity by Bardeen, Cooper and Schrieffer, it was for several years a matter of concern to render the theory charge conserving and gauge invariant. I have been reading the article by Y. Nambu, Phys. Rev. Vol. 117, p. 648 (1960) who uses Ward identities to...
  44. D

    Superconductivity in type1 and type2?

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  45. S

    How Does p_x + i p_y Symmetry Arise in P-Wave Superconductors?

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  46. C

    Superconductivity Critical B field, thermodynamical proof

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  47. T

    Superconductivity: difference between s-wave and d-wave

    I'm very new to superconductivity and I've tried searching for the difference between s-wave and d-wave superconductivity but to no avail. I find it's often mentioned but never explained. I assume it's fairly basic, but if anyone has an explanation or some references I can check, it would be...
  48. D

    Broken symmetry, superconductivity and all that

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  49. S

    How does a superconductivity cable achieve zero resistance?

    Well. I have the image of the question. http://img99.imageshack.us/img99/6834/question5.png Question b)ii). I know that the total resistance of the cable is 0 even though the copper itself still has resistance. I just want to know how the combination of the Superconducting filaments...
  50. MTd2

    How is 3D d-wave superconductivity band?

    Please, I found this (the 4 lobe object in the center): http://www.physics.utoronto.ca/lecture-and-seminar-series/colloquium/events/tsuei.jpg But is it the same throughout the z axis, or does it vary significantly?
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