Timeline for Is a superconductor 'perfect'? i.e. does current flow forever without decaying?
Current License: CC BY-SA 4.0
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| Aug 21, 2022 at 16:42 | comment | added | jp314 | But that example of a small iron crystal is just for a single non-zero value of magnetization. A superconducting loop could have any of a (nearly ?) continuum of values of current flowing. | |
| Aug 7, 2022 at 18:14 | comment | added | rob♦ | @jp314 Compare a superconductor with nonzero current in its ground state with iron, which has nonzero magnetization in its ground state. Bulk iron may slowly demagnetize, but that happens as the boundaries between completely-magnetized "grains" migrate to minimize the energy stored in the external magnetic field. A small iron crystal with no defects is spontaneously magnetized in its ground state, and will stay that way. | |
| Aug 7, 2022 at 18:09 | comment | added | jp314 | and not about physical changes (chemical, radioactivity; loss of refrigeration). For instance a piece of Copper, or a YBCO superconductor (perhaps the behaviours are different ?). | |
| Aug 7, 2022 at 17:54 | comment | added | jp314 | I am asking about a sensible current -- not minor (quantum ?) fluctuations. If the temperature is kept well below the transition temperature, and there are no external disturbances, does the current decay ? e.g. given that temperature is somewhat a statistical phenomenon, do small localized 'temperature' perturbations cause localized non-zero resistance regions and consequently resistive losses ? | |
| Aug 7, 2022 at 17:41 | history | answered | Andrew Steane | CC BY-SA 4.0 |