What is Superconductors: Definition and 144 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. Mayhem

    How do YBCO superconductors react with hydrochloric acid?

    If we consider YBCO 123, YBa2Cu3O7-δ, what would the expected reaction if dissolved in aqeuous HCl? I have tried to find resources about this online, but the closest I got was related to Cl-containing YBCOs, and not actual reaction stoichiometry. My intuition tells me the metal centers (Y, Ba)...
  2. A

    I Looking for resources about tunneling effect on two delta functional barriers

    Hello. I have 2 questions. First, I've read theory of tunneling effect but I need theory of two and more delta functional barriers. How do you think where can I read more about it? I need it for superconductors. And second, where can I find how to add magnetic field to theory of it? How it...
  3. StanislavD

    A Experiments for temperature dependence of persistent supercurrent?

    Imagine, in a mercury ring (superconductivity below Tc=4.15 K) we establish a persistent supercurrent. Then we organize temperature cycles (T-cycles) in the cryostat, from 3 K to 2.5 K and back. According to the BCS theory of superconductivity, the pair density decreases at warming, i.e. a not...
  4. sol47739

    I Superconductors and currents

    How are currents injected into a superconductor? And can you regulate the velocity of the current afterwards? Since the magnetic field can’t penetrate? What would happen if you tried to make the Cooper pairs approach relativistic speeds? Would the superconductor stop being in its...
  5. sol47739

    I Superconductors and moving/accelerating charges

    How do one get the electrons to move inside a superconductor? Since I have understood superconductors repel magnetic fields due to the Meissner effect, or is that when the charges already are moving within the superconductor? If so how did we get them o move from the beginning? Can you make...
  6. SBrownJC

    B Do materials surrounding magnets affect how superconductors levitate?

    I'm currently doing an experiment with magnetic levitation but I don't know if my independent variable will even affect my results at all. I am planning on building a rail of magnets and levitating a type 2 superconductor on it. I wanted to change the material surrounding the rail of magnets...
  7. W

    Quantum Textbooks or articles as an introduction to superconductors

    Hi, As an Undergraduate student I'm looking for some textbooks and/or articles as an introduction to superconductors. I have a homework to do as final project not exactly in this field but related. and I would like to understand what exactly is a superconductor as well as use those textbooks...
  8. A

    A Quantum computing with superconductors

    I have some questions to this Ansatz and I would really appreciate it if I can get some insight: 1. What is the current status of gate fidelity and what are the current struggles to improve it? 2. Same question but with coherence times. 3. What are the current issues with scalability? 4. Could...
  9. R

    Current in superconductors

    Hello! Recently, I became interested in superconductors. And I talked to professor in my uni. Here's my question, since superconductors have zero resistance by definition, so, in stable condition (after passing transient phase) the current should be infinite. Which implies that according to...
  10. A

    A The difference between the binding of molecules and superconductors

    Molecules and superconductors bind due to overlaps of the wave functions of the electrons. 1. What is the difference between these two then? 2. Why can't we look at molecules as a macroscopic wave function?
  11. iVenky

    I Is London depth in superconductors analogous to skin depth?

    London penetration depth that's defined for superconductors has a similar equation to skin depth in conductors derived from maxwell's equations. Are they equivalent?
  12. DaniV

    A Mapping the Phase Space of Type II Superconductors

    Due to my lab work I want to try map the phase space that created with critical external magnetic field H_c and the critical current J_c through the superconductor of type II. the critical transition happen from the Abrokosov phase to the non-superconductor phase, occurred by the fact that in...
  13. hagopbul

    A High pressure superconductors

    Hello to all Can we consider the core of the Earth to be a superconductor ,for example Aragon national laboratory hinted for some thing like that https://www.anl.gov/article/nickel-for-thought-compound-shows-potential-for-hightemperature-superconductivity That been said , what test could...
  14. Kevin J

    How is current induced in superconductors?

    Assume resistor R/heated segment is 5 Ohms, while the path in the right hand side remains 0, thus, total resistance is 0 Ohms, my question is how could current be induced if potential difference is 0(due to zero total resistance) Or is it probably because of the batteries internal resistance?
  15. K

    I Superconductors and Wiring

    Zero resistance in wiring seems to be the technology in the future. Any resistance in the transmission wiring acts like loads so it's like the current wastes itself on the resistances in the wiring and heat that occurs. So lossless wiring seems to be the ultimate goal. In Large Hadron Collider...
  16. B

    B Cooper pairs and Superconductors

    How are Cooper pairs being in the same quantum state responsible for superconductivity? Why does them being in the same quantum state matter? Please no complex mathematics, I don't understand that stuff :)
  17. J

    Magnetic Levitation (electromagnets?) for an 11th grader

    I don't know if this is the right place to put this, but I am very lost as of right now. I am doing my 11th grade physics project on magnetic levitation. From what I can understand, there are 2 "main" types of magnetic levitation, them being with superconductors and with electromagnets. For the...
  18. J

    I Detecting WIMPs with superconductors?

    If a weakly-interacting massive particle interacted with an electron in a classical superconductor would it break up a "cooper pair" and thus lead to extra electrical resistance? If so perhaps the loss of superconductivity in a 2-d array of superconducting wires could be used to detect the flux...
  19. S

    Solid State Topological Superconductors -- Looking for introductory textbooks or study materials

    Dear All I am trying to study Topological superconductors but i have no idea about it. Can anyone suggest me an introductory book to start with.
  20. R

    I Superconductors and the Meissner effect

    So I am writing a paper on superconductors, and i am trying to explain the meissner effect. However i seem to be running into conflicting information. I hoping some one can help clarify. The effect happens, when a magnet creates a change in flux, causing a induced current in the...
  21. gonadas91

    High temperature Superconductors: Cuprates

    Hi everyone, I am about to finish my PhD and need to start thinking about trying to move somewhere else. One line of research that caughts my attention is that of the cuprates, and the study of their phase diagram. I would like to know if someone can suggest a very recent book or review article...
  22. Tazerfish

    Are superconductors perfect reflectors?

    To my current(somewhat pathetic:wink:) knowledge the reflection off metal surfaces happens because the changing electric and magnetic fields cause "mini currents" or charge redistributions which produce their own electromagnetic waves identical to the incoming ones or in other words the...
  23. B

    I Superconductors and spacetime question

    I am not a physicist and don't understand a lot of it, I can't do maths, but in all other areas I consider myself an above average educated civilian. I had a strange dream and it got me thinking. Has anyone ever done a synchronized atomic clock test with a superconducting element? Like placing...
  24. D

    I Magnetic Field Penetration in Superconductors

    Consider a 5 meter by 5 meter and 1cm thick superconducting plate, now place a very strong neodymium magnet against the underside of the plate.The plate is big enough so that the magnetic field does not go around the plate. Does a magnetic field penetrate the plate or is it blocked completely...
  25. T

    Linear Induction Coilgun with superconducting projectile

    If you have: A Linear Induction Coilgun, basically like a series of Induction Furnaces, using copper coils with high AC current at a high frequency. Where the projectile traveling inside those coils has a shorted superconducting coil around the outside of it, embedded in the ceramic projectile...
  26. J

    Calculate superconductor's magnetic susceptibility from Inductance

    Homework Statement Hi, I have some data taken on voltage and resistance of a coil part of a yttrium barium copper oxicde (ycbo) superconductor. I have no information about the coil itself. A thermocouple attached to the superconductor also measured the temperature of it as it was cooled. This...
  27. Davephaelon

    Entangled electron in High Temp Superconductors

    I was reading an interview of Dr Subir Sachdev in the latest online issue of Quanta Magazine, and he mentions that Cooper pair electrons in the high temp superconductors (HTSC's) are globally entangled with one another, but in the low temperature (type 1) superconductors, they are not, and I...
  28. D

    Superconductors in magnetic fields

    Does a superconductor experience any forces acting upon it when it is passed through a magnetic field?
  29. T

    Buy Small Superconductors Online | Explore the World of Superconductivity

    Hello, I have been looking at superconductors lately and was wondering if there was anywhere I could get a small superconductor online. I realize for it to actually conduct it must be incredibly cold, but I was wondering where I could get a metal that allows for superconduction.
  30. S

    Magnetic levitation - superconductors

    The question I have is rather simple and straightforward so here it is: How much weight can a magnet support and still levitate above a superconductor? We all know about super fast levitating trains and I want to use the same idea for something else. However before looking deeper into magnetic...
  31. Robin_Shorrosh

    Exploring Quantum Computing: Making a Qubit with Josephson Junctions

    I am working on a project for our local science fair and decided on researching quantum computers. (This is what my focus will be in college.) Though, I expect to work on this far past the time allotted for that. I would like to build a superconductor based qubit using Josephson Junctions. The...
  32. Nemika

    Can superconductors conduct electricity at absolute zero?

    I've just learned that the conductivity of super conductors increases with decrease in temperature and it becomes infinite at absolute zero. But I thought that all motion ceases at absolute zero. So how can current flow in such conditions? And how can its resistance become zero as some...
  33. R

    How dopant enhances the superconductivity of BSCCO

    Good day! i really need your help, I want to know the effect of Dopant (for Example Manganese) in BSCCO (for example Bi-2212) on it's Resistivity? i read some articles saying it increases the critical temperature of the superconductor, But it didn't explain why, and how is that related to the...
  34. DoobleD

    Why Faraday's law works with superconductors?

    1: Faraday's law states that a changing magnetic flux induces a voltage. 2: Voltage is the integral of E field with distance. 3: In a superconductor, or equivalently an with idealized wires having 0 resistance, there can't be any electric field inside. Thus, voltage in a superconductor should...
  35. Jess H. Brewer

    Who is Jess Brewer and What is Her Fascinating Field of Study?

    Hi, I'm a retired (since 2011) Physics prof from the University of British Columbia. I originally set out to get a PhD in Physics to increase my credibility as a science fiction writer, but I discovered a field* that was so cool it was like being a character in my own SF novel. In short, I got...
  36. D

    Shielding magnetism with superconductors

    If I surrounded a wire carrying current with a superconductor would the magnetic field from the wire be blocked from the outside?
  37. E

    Band Gap in Superconductors

    Hi all, I am currently writing a report about superconductors, and am currently reading about how the band gap shows that single electrons are not the charge carriers responsible for superconductivity. However, I was confused when I read that electrons are fermions and as such there are no band...
  38. L

    Magnetic field behind superconductors

    Hej Guys, Is there a way to calculate the magnetic field behind a superconductor? I mean the model is like some simple block magnet and a bigger superconductor plate to try to shield the magnetic field. How strong the magnetic field would be above(behind) the SC? B, H is given. Also is the...
  39. Jimster41

    From black holes to superconductors: Stanford video

    Hope this Link works. I thought this guy was great, for the layperson looking for more than the usual fluff. Might nice to give SITP some heavy "likes". Maybe they will do more. Sorry not sure what forum this was most appropriate for...
  40. D

    Surface Barrier in Type 2 Superconductors

    If a field line is moved into a superconductor it meets resistance. This resistance is modeled by adding an image flux thread outside the superconductor which then attracts the flux thread being moved into the superconductor. Why is this attractive force an accurate model of the resistance a...
  41. T

    Gibbs Free Energy in Superconductors

    When reading some material concerning Ginzburg-Landau theory of superconductors, I got the following sentence: The appropriate thermodynamic potential for describing a superconductor in an applied magnetic field is the Gibbs free energy ##G## (natural variable ##H##) and not the Helmholtz free...
  42. A

    What can be found in the MT curves of superconductors?

    I am confused about the magnetic susceptibility vs. temperature curves (or MT) of superconductors (SCs). In the normal conduction state (I measured from 4.5K to 300K), the susceptibility curve can obey the Curie-Weiss law. But when I fitted the data via the Curie-Weiss law in a different...
  43. J

    Metal Superconductors and Negative Temperature

    What would happen to a metal superconductors taken below zero to a negative temperature? Would it loose its superconductivity?Regards, JDM
  44. J

    Superconductors and Space

    This might be another silly question but here it goes; I was reading how " A superconductor excludes the lines of magnetic force" http://www.aip.org/history/mod/superconductivity/01.html and I'm wondering if a giant superconducting magnetic field could help protect spaceships/space stations...
  45. R

    What are the latest metallic superconductors discovered in the past decade?

    Hi Guys, Please give me an example or list of Metallic superconductors (new metallic superconductors (year 2010-2014). thanks :).
  46. P

    Ideal Transformer with Superconductors?

    Just had an idea that raised a few questions and I can't find any relevant data on after a bit of searching so thought I'd ask here. If you were to make a transformer entirely encased in superconducting material would it result in a significant step toward and ideal transformer or is magnetic...
  47. J

    Superconductors and Space: Can Electricity Bend Reality?

    Hi! I was wondering that if you could put enough electricity into a superconducting coil if it would be powerful enough to bend space?
  48. M

    Superconductors and outer space

    What would happen to cosmic rays if you put superconductor material on the hull of a spacecraft ? Would the flux trapping effect trap the cosmic rays? Could the superconductor protect the spacecraft from cosmic rays? Could it be possible to create a superconductor magnet that can produce a...
  49. H

    Knotted Solitions in multiband superconductors

    According to Prof Egor Babaev and others, it seems possible to have knotted solitons in certain superconductors. He has had numerous articles published in Physical Review and Nature. The most understandable one I've found is Hidden symmetry and knot solitons in a charged two-condensate Bose...
  50. C

    Superconductors and the Meissner Effect

    So I'm a little confused about the Meissner Effect. If we have both a perfect conductor and a superconductor (both above Tc) and place them in a magnetic field and lower their temperatures so they exhibit their respective properties, the magnetic field inside the perfect conductor persists...