Magnetization of a current-carrying superconducting Corbino disk

Abstract

We calculate the hysteretic response of a current-carrying type-II superconducting Corbino disk subjected to a perpendicular applied magnetic field. For a disk containing remanent flux in zero field, our theory predicts that applying a radial transport current or raising the temperature at fixed current will cause the magnetic flux to be expelled from the sample. For a disk initially containing no magnetic flux but carrying a radial current, we find that as a perpendicular magnetic field is applied, magnetic-flux penetration occurs in three stages: (i) the magnetic flux gradually penetrates from the edges of the disk until an instability occurs, (ii) there is a rapid inflow of magnetic flux into the disk’s central region, which becomes resistive because the radial current density there exceeds the depinning critical current density Jc, and (iii) magnetic flux continues to enter the disk, while persistent azimuthal currents flow in an outer annular region where the net current density is equal to Jc. We also calculate the behavior of a current-carrying Corbino disk subjected to an ac magnetic field.

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