According to this article:
Superconductors contain tiny tornadoes of supercurrent, called vortex filaments, that create resistance when they move.
Does this mean that our description of zero Ohmic resistance in superconductors is a little bit too enthusiastic?
Answer
I think that since superconductors were originally discovered because they exhibited electrical resistances indistinguishable from zero that zero electrical resistivity may have originally been the defining characteristic of a superconductor. But as more was learned about superconductors and the superconducting state it was realized that superconductors can exist in a mixed or vortex state consisting of normal-state vortices in a superconducting medium, and such a system can exhibit energy dissipation due to the movement of the vortices which results in an electrical resistance that is not strictly zero. So, yes, I guess you could say that the use of the term "superconductor" when these materials were first discovered could have been a bit "too enthusiastic" since it suggested that absolute zero resistance was an essential, defining characteristic of superconductors when it's not.
Not an expert in superconductivity and maybe someone else will chime in, but from my perspective as an experimentalist I would say that an operational definition of superconductivity is a very low electrical resistance combined with the Meissner Effect (i.e., magnetic flux exclusion).
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