What is Superconducting: Definition and 84 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. Hak

    Coaxial semi-infinite solenoid and superconducting disc

    I have no idea how to deal with the problem. Do you have any hints, please?
  2. pinball1970

    Airbus & CERN Partner to Promote Superconducting Tech for Clean Aviation

    https://www.airbus.com/en/newsroom/press-releases/2022-12-airbus-and-cern-to-partner-on-superconducting-technologies-for "Airbus UpNext, a wholly owned subsidiary of Airbus, and CERN, the European Laboratory for Particle Physics, are launching a project to evaluate how superconductivity can...
  3. StanislavD

    A Superconducting and normal electrons are not interchangeable

    An interesting paper in NATURE "A superconductor free of quasiparticles for seconds" https://www.nature.com/articles/s41567-021-01433-7 showing that superconducting (paired) electrons don't hop into normal states for seconds. The measurement device detects single pair-breaking-events for a large...
  4. J

    Preparing for a Quantum Computation Course: Superconducting Qubits

    Summary:: Looking for articles/books to prepare myself for the course: Quantum computation with superconducting qubits Hello everyone. I am about to take a course in Quantum computation with superconducting qubits and I am searching for material to prepare it. I took a first course on that...
  5. maajdl

    I CQED understanding superconducting qbits circuits

    I have read a little about cqed, "circuit quantum electrodynamics". I would be interested in references to dig a qbit deeper in this topic! I have seen lumped circuit diagrams for superconducting qbits. The correspondance between classical and quantum models for these circuits is really...
  6. S

    What limits superconducting machine power density?

    Hi. There has been a fair amount of research into electric generators and motors with superconductive coils. If traditional iron cores is used that obviously limits the power density because of the iron cores magnetic saturation point. But for coreless/ironless designs i don't understand what...
  7. hutchphd

    I Room Temp Super Conductor: Break Out the Champagne?

    Summary is from abstract in Nature. Anybody know whether this is a big deal ?. It looks technically challenging (very high pressure) but great oaks from little acorns. I'm not current in superconductivity.🔎...
  8. E

    Compression of a superconducting spring

    Let the length of the spring be ##x##, so that the extension in any given configuration is ##\delta = |x_0 - x|##. The magnetic flux through such a coil is $$\Phi = \frac{\mu_0 I N^2 A}{x}$$The fact that the coil is superconducting means that the flux linked will always remain constant even with...
  9. TheBigDig

    Derive an expression for the applied field of a superconducting wire

    So far the best I've been able to come up with is to use ##\vec{B} = \mu_0 \vec{H}## which gives me i_c = H 2\pi r j_c = \frac{H 2\pi r}{\pi r^2} = \frac{2H}{r} \therefore B = \mu_0 \frac{r j_c}{2} I'm fairly confident this is just terrible math and physics on my behalf but I'm struggling to...
  10. T

    B Has anyone ever built a superconducting quenchgun?

    Has anyone ever built a functioning superconducting quenchgun? Or has the theory or practicality of it's operation ever been questioned or disproved?
  11. N

    China's Experimental Advanced Superconducting Tokamak (EAST)

    A team of scientists from China's Institute of Plasma Physics announced this week that plasma in its Experimental Advanced Superconducting Tokamak (EAST) would be ready to begin attempting to generate more energy than it uses, in a world first. I am dubious about more news that comes out of...
  12. hagopbul

    A Is the Earth's core a potential high-temperature superconductor?

    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...
  13. M

    Superconducting Magnetic Energy Storage (SMES)

    I cam across SMES (Superconducting Magnetic Energy Storage) while researching superconducting and had a few questions I'm hoping to have answered. 1. I have read that SMES devices are primary used in the event for short interruptions in power, and aiding in efficiency in the power grid. Can a...
  14. Sebastiaan

    How To calculate the Power required for a Superconducting Magnet

    Alright, I'm trying to calculate the power requirements for a 30 Weber =( 30 Tesla/m2) Strong magnet According to this document it would require about 88 MW using a steady-state copper coil magnet The question is, how much power is required to do the same using cryogenicly cooled...
  15. R

    Why does the Japanese Maglev train use superconducting magnets

    My little home made air-core solenoid makes 1.5T, why is it that superconducting electromagnets often aren't stronger than one would expect. Take the japanese maglev train for example: http://www.supraconductivite.fr/en/index.php?p=applications-trains-maglev-more According to this article the...
  16. DeathbyGreen

    A Zero Energy Wavefunctions in 1D superconductor

    \bf{Setup} Hi! I am trying to derive the wavefunctions of the zero energy solutions of the Schrodinger equation in a 1D p-wave superconductor (Kitaev model). I am starting with the Hamiltonian $$ \begin{equation} H = \left[\begin{array}{cc} \epsilon_k & \Delta^{\ast}_k\\ \Delta_k & -\epsilon_k...
  17. John Morrell

    How are Superconducting Coils charged?

    Superconductors can be used to store energy in the form of magnetic fields, because the current in a superconductor can persist indefinitely. In fact, some large power grids are already using this as a way to regulate power flow in the grid. My question is how are the coils "charged"? How do we...
  18. Robertphysics

    Superconducting motor thought experiment/ questions

    I am sorry but this question I have described is a long one. Ok so before I start a quick background , I have read and understand the Meissner effect of the superconductor expelling it’s magnetic field , also I understand that superconductor has zero resistance so a once induced or applied...
  19. 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...
  20. N

    Can Superconducting Sheets Reflect Gravity?

    I read this article by MIT Technology Review https://www.technologyreview.com/s/412674/if-superconducting-sheets-reflected-gravitational-waves/ which I believe states that thin sheets of super conducting material reflect gravity. is this article true or am I just reading it wrong. I know this...
  21. A

    Superconducting Magnetic Energy Storage device size

    How large would a superconducting magnetic energy storage device be if it were to safely carry 100 kilowatt-hours of energy? How much cryogen (liquid nitrogen) would it consume per hour if the device were made from high-temperature superconducting materials (YBCO or similar).
  22. H

    Current induced in concentric superconducting loops

    Homework Statement Suppose you have two superconducting loops, concentric, in a plane. Also suppose that their radii, R2 (outer) and R1 (inner) have the same order of magnitude (so you can't assume B through the inner loop is constant everywhere over the inner loop's surface.) If a constant...
  23. wavepax

    Superconducting Resonator matches 3 Degree Kelvin Spectrum

    Carver Mead writes in his book, "Collective Electrodynamics", that experimental evidence indicates a superconducting ring and capacitor resonator circuit will increase from zero voltage (scalar potential difference) to an energy matching a 3 degree Kelvin black body radiation spectrum...
  24. PhiowPhi

    How would superconducting motors/generators work?

    How can superconductors improve motor/generator's performance? A superconductor will expel a magnetic field, how can it generate a Lorentz force in the case of a motor, and a induced EMF in the case of a generator? It's makes sense that we can only improve the windings of the electromagnet...
  25. HanningWu

    Why use mercury to verify isotope effect in superconducting?

    Because mercury has a low melting point? What are the advantages of mercury in the isotope effect experiment? Can we use some other materials?
  26. I

    Force on a superconducting cube

    Hi everyone, I need some help to look if I did these calculations right.Let us assume a three dimensional magnetic field: ##\vec{B}(x,y,z) = B_x(x,y,z)\hat{x} + B_y(x,y,z)\hat{y} + B_z(x,y,z)\hat{z}## The equation for the force on a superconducting particle in a magnetic field is given by...
  27. D

    Force between two superconducting wires

    Consider two parallel superconducting wires. Both the wires carry the same current and the current is going in the same direction. do they experience a magnetic force attracting them together? Or do their magnetic fields behave differently?
  28. D

    Exploring the Conservation Law for Magnetic Flux in Superconducting Circuits

    There is a conservation law for superconductors " the flux through a superconducting ring cannot change". This can be shown using Faraday's law: - E.M.F=-d/dt (BA) where B is the measured magnetic field passing through the ring and A is the area enclosed by the ring therefore for a ring...
  29. lfqm

    Introduction to superconducting quantum circuits

    Hi guys! I'm making my Phd on cavity QED but wish to move towards superconducting quantum circuits, could you give me some good references (articles or books) at an introductory level (for self-study)? Thanks in advance
  30. L

    Calculate power required to operate superconducting magnet

    Dear Friends, The great problem lies in here : I have calculated the power requirement of an electromagnet. That Its huge . To minimize this power requirement I would like to see if its possible with super conducting magnet, but I am having a problem, because the power requirement are so low...
  31. Z

    Superconducting magnetic energy storage, practical?

    Storing energy in a system means to raise the internal energy of it. A system could be in superconducting phase because the latter has correspondingly lower internal energy. How can energy be stored in a phase that has the lower energy? When energy is injected into the system, it would leave...
  32. MagnetDude

    Superconducting magnet with HTS wire

    Hey guys, I am building a superconducting magnet. The wire I have is extremely thin, and is flat. To put it more into perceptive it has a width and height. When I wind it into a magnet, it is more like a disk coil, or racetrack coil. Because it has a different geometry than most other...
  33. T

    Can Superconducting Generators Improve Efficiency in Hydropower Plants?

    i believe that superconducting generators are now in use,We have hydropower plants in our country still using the conventional generators. My idea for my masters dessertation would to replace these generators with the superconducting ones, and hopefully get better efficiency. Would this make a...
  34. C

    Breaking superconducting state

    When the B field gets too high it breaks the superconducting state. And then the B field can exist inside the conductor. When the field increases to point where it breaks the state is this because the cooper pairs flowing near the surface experience a force on their spin and then break them...
  35. kq6up

    Quantum Superconducting Circuits Class?

    I am wondering if this class is senior undergrad level or graduate level. Here is a published PPT from the lectures of this class. http://bit.ly/1izPCIW The material is fascinating. I understand it enough to be intrigued, but I cannot unpack it all. Thanks, Chris Maness
  36. Z

    Superconducting Capacitor for Energy Storage?

    Hi I was about to fall asleep last night and was thinking about breakdown voltage, when electrons are pulled from the surface of a conducting plate and form a channel that discharges a capacitor. This is called a vacuum arc, some other keywords are thermionic emission and work function...
  37. B

    Are superconducting galvanic cells possible?

    My (chemistry) textbook states that maximum work is never achieved in a galvanic (electrochemical) cell due to frictional heating. I've been wondering, could a cell be made with superconducting wires, cathodes, and anodes in order to achieve maximum work? Would this violate the law of entropy?
  38. S

    Is the Lenz Effect in a superconducting magnet strong enough to stop a bullet?

    After watching a fascinating youtube video demonstrating the Lenz Effect using a 1.5T MRI machine and an aluminum block, I was wondering if it would stop a bullet fired along the axis of the machine. If so, would there be any defensive military application?
  39. V

    How fast can you 'switch' between superconducting and normal modes?

    The title, basically. If we're at a temperature below the critical temperature (let's just say for a Type 1 superconductor) and an applied magnetic field less than the critical magnetic field, it will be in the superconducting state. But if we increase the field beyond the critical point, it...
  40. V

    Zero resistivity in superconducting state

    Hi everyone, - Could you explain for me the meaning of "net" in the phrase "small net attraction between electrons" in superconductivity, (or synonym of it)? - We usually say that BSC theory explains the superconductivity of conventional superconductors, one feature of superconductivity is...
  41. O

    Can an Enclosed Superconducting Loop Generate Electromotive Force?

    Hi, If I take an enclosed superconducting wire loop, and apply a time dependent magnetic field in the space enclosed by the wire ( and therefore a time dependent magnetic flux) , this should induce electromotive force ( according to faraday's law). However any potential difference should not...
  42. Loren Booda

    Semiconduction in a superconducting circuit?

    Can a fundamentally superconducting circuit include semiconduction?
  43. J

    Energy stored in superconducting magnet

    Hello 8 months ago we discharged a 3 Tesla superconducting magnet which is part of old FT-ICR mass spectrometer. Magnet was charged some 20 years ago and working since (which is exceptionally long since it worked in persistive mode, which means no charging in all this time). During...
  44. B

    Exploring the Mysterious Attraction Between Permanent & Superconducting Magnets

    It is possible for a permanent magnet to be attracted to a cooled superconductor magnet as shown in many experiments, but why does it not attract the permanent magnet to the point that their surfaces come in direct physical contact similar to the attraction that causes two permanent magnets join...
  45. D

    Designing Superconducting Magnets: A Beginner's Guide

    I'm trying to learn the basics of designing superconducting magnets for guiding particles, but I'm having a hard time knowing where to start. I don't have a background in this field (besides EM classes). Right now I'm thinking about ordering "Superconducting Magnets" by Wilson and studying...
  46. X

    Field in a superconducting torus

    A question:- Is it possible to create a magnetic field inside a perfectly superconducting torus if you did not have any to start with? I am talking about a field that goes all the way around the torus, not one that goes partway and doubles back. I am having trouble visualizing how the field...
  47. T

    So I need to make a superconducting tube.

    Preferably YBCO or BSCCO as I only have liquid nitrogen at my disposal. The issue I'm running into is that no HTS producer makes superconductors in this configuration. I was thinking of just buying the YBCO powder and then either pressing it into the desired shape or mixing in a binder of some...
  48. T

    Trying to make a Superconducting tube

    I'm doing an experiment which requires the fabrication of a superconducting hollow cylinder but I am unable to find a firm which does custom manufacturing of this nature. I have found numerous which sell the high Tc powders (YBCO BSCCO). My question is if I do just buy the powders what could I...
  49. J

    How many Ampere in a superconducting spire?

    As far as I can understand, after inducing a current inside a superconducting ring or spire, the current keeps flowing into the ring "for ever". Is this correct? Since electrons have no "friction" against the superconducting lattice, does this mean that I can virtually accelerate them...
  50. T

    Lorentz force on superconducting wire?

    Hello, I've been trying to puzzle this one out and even the mighty internet has not been particularly helpful, so here goes: Say you have a current carrying copper wire perpendicular to a magnetic field. Let's give some values for clarity: the length of the wire is 1m, the current is 3A...