Superconductivity Definition and 32 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. hudsonj

    Intro Physics Pop-sci books about condensed matter physics or superconductivity?

    I was wondering if anyone knows of any technical pop-sci books about condensed matter physics and/or superconductivity that are at the technical level of something like the "A Very Short Introduction" series or the Feynman lectures. That is, something that goes sufficiently into depth into the...
  2. StanislavD

    A Superconducting and normal electrons are not interchangeable

    An interesting paper in NATURE "A superconductor free of quasiparticles for seconds" showing that superconducting (paired) electrons don't hop into normal states for seconds. The measurement device detects single pair-breaking-events for a large...
  3. orochi

    Learning about condensed matter physics as a particle physicist

    I am on my first year of my master's degree in nuclear and particle physics, and right now i am ending my first semester, where i decided to take a course in physics of semiconductors. As i end this semester i start to wonder if there was any use in learning about this subject, as it seems like...
  4. mcas

    The Cooper Problem in tight binding

    We have a one dimensional lattice with a lattice constant equal to a (I'm omitting vector notation because we are in 1D). The reciprocal lattice vector is k_n=n\frac{2 \pi}{a}. So to get the nearest neighbour approximation I need to sum over k = -\frac{2 \pi}{a}, 0, \frac{2 \pi}{a}. If I...
  5. jk7297

    A BCS energy and Cooper pair probability amplitude

    This question is for those familiar with the BCS theory of superconductivity or familiar with R.D. Mattuck's book “A Guide to Feynman Diagrams in the Many-Body Problem.” I am working my way through the book, and I am stumped by some of the problems at the end of chapter 15 (superconductivity)...
  6. 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...
  7. M

    I General relativity - covariant superconductivity, Meissner effect

    I am doing a project where the final scope is to find an extra operator to include in the proca lagrangian. When finding the new version of this lagrangian i'll be able to use the Euler-Lagrange equation to find the laws of motion for a photon accounting for that particular extra operator. I...
  8. A

    I How do Cooper pairs carry a current with zero net-momentum?

    One of the first starting points of introducing BCS theory in a superconductor is applying a theorem stating that the ground-state of a quantum system has an expectation value for its momentum of zero. You then use this to say that an electron must pair with another electron of equal and...
  9. A

    A Spin dynamics and the Pauli exclusion principle

    For high temperature superconductivity, people usually say two quasifree electrons are pairing, one is spin up and the other one is spin down. So, if that is the case, each two electrons will have zero spin angular momentum. Since the superconductivity is the magnetic properties and spin is the...
  10. pangru

    Physics Career in cuprate high temperature superconductor physics

    Hello, I am interested in physics of cuprate high temperature superconductors (Cuprate_SC) However, I heard that it is "out-of-dated" topic in solid state physics and almost impossible to find group/foundation to do research in this field. I am doing PhD right now and I consider moving...
  11. 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...
  12. ChinoSupay

    A Can a degenerate gas of electrons be a superconductor?

    If is yes, under which conditions?
  13. fluidistic

    I Impact of superconductivity on mechanical properties?

    It is often said that the mechanical properties of metals are mostly due to their free electrons. I'm talking about malleability, ductility and hardness. So, when they suffer a superconductive transition, I expect a drastic change in their mechanical properties, but I haven't found anything on...
  14. li dan

    Can an aircraft using a geomagnetic field generate lift?

    As shown in the figure, the aircraft includes a geomagnetic field convergence layer, which is a superconductor material. The geomagnetic field convergence layer repels the direction of changing the geomagnetic field, so that the geomagnetic field passes between the upper and lower converging...
  15. DariusP

    Are flux vortices predictable?

    What I mean by that - is it possible to model a system and somehow obtain them as a result? (in FEMM 4.2 or Comsol for example) Or is their forming still not yet explored enough?
  16. J

    Solid State Sources to learn about Topological Superconductivity

    Greetings. Does anyone know about any good places to learn about topological superconductivity from? Thanks in advance!
  17. Tspirit

    Superconductivity for light beams?

    As is well known, superconductivity is described as a property of zero-resistance for electrical current, however, I want to know, is there any material with superconductivity for light beams, in which the light beams can propagate with no losses?
  18. G

    I Problem I have with second London equation

    Second London Equation, which is supposed to represent the current in a superconductor. (SI units) ∇×j=-(ns e2/m) B. Lets have a look at a super-conducting wire. The magnetic field is: B=μ0Ir/(2πr) Where Ir is the current enclosed by the radius r. We are talking about the current at some depth...
  19. DeathbyGreen

    A Nambu Spinor Notation in Kitaev spinless p-wave model

    Hey all! Thanks for reading. I'm currently following along in some reading and had some trouble with re-writing a Hamiltonian in Bogluibov-de Gennes form using Nambu notation (Nambu spinors). Here is the low down: Say we have a Hamiltonian: \frac{1}{2} \sum_{i=1}^{N} c_{i}^{\dagger} D c_{i} +...
  20. DeathbyGreen

    P wave superconductivity

    Hello! So I'm really stuck in a personal quest to derive Kitaev's 1D p wave superconductivity model, and I'm stuck on the seemingly simplest part. 1. Homework Statement In the Bogluibov transformation, we get two coefficients from the equations |v_{k}|^{2}+ |u_{k}|^{2}= 1...
  21. J

    I Is it possible to calculate Tsupercon from the unit cell?

    Hi folks, It is an elementary question for people expert in superconductivity. I know there is a theory, the BCS theory, and the GIzburg Landau theory too that apparently explains superconductivity. My question is, if I give you a unit cell would you be able to tell me the temperature at...
  22. A

    Flux Pinning in a type 2 SC Using an AC Electromagnet

    When a supercooled type two superconductor is subjected to a static magnetic field, the superconductor pins to the flux of the field (the mixed-state meissner effect is apparent). What happens if it is subjected to a continuously changing magnetic field, assuming the superconductivity takes...
  23. D

    I Difference between Zero-Field Cooling and Field Cooling

    I am currently doing a experimental project work on superconductors. I am supposed to study properties of FeTeSe. I am having trouble understanding the difference between Zero-Field Cooling and Field Cooling. In both cases, I am measuring magnetization with varying temperature (from lower to...
  24. Hanarchist

    Creating a Maglev Track using Electromagnets?

    Hi All, I was wondering how I would go about creating a circular maglev track using electromagnets? The idea is to have more control over it and to eventually write a piece of code that would allow changes in the strength of the magnetic field potentially? I was just wondering how it would work...
  25. 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).
  26. W

    Importance of Fermi Surface in Cooper Pair Formation

    Hello, This problem is about cooper pair formation and what happens with the calculations if there is an attractive potential between electrons but it is not in the presence of a filled fermi surface. 1. Homework Statement Two electrons just above the filled Fermi Surface of a material can...
  27. pangru

    Underdoped Cuprates

    What does underdoped cuprates mean? As I guess cuprate is underdoped when hole concentration is less then optimal doping. Is it correct?...:rolleyes: Thank you very much in forward
  28. N

    Difference between Superconductivity & Ballistic Conduction

    I read in a book "Optoelectronic Integration: Physics, Technology and Applications" edited by Osamu Wada. Ballistic Conduction and Superconductivity are both electron transport that are not affected by the collisions and scatterings. Ballistic conduction or Ballistic transport occurs when the...
  29. F

    Good Books on Quantum Computing and Quantum Mechanics

    Hello guys, I will be starting my M.S Program in Solid State Electronics and was also curious about looking into quantum computing/superconductors. So can you guys suggest introductory levels books on quantum computing and and superconductors? I have an okay background in Physics (just...
  30. D

    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...
  31. 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...
  32. D

    Friction in Maglev 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...