Magnetization of a current-carrying superconducting Corbino disk - art. no. 184507

We calculate the hysteretic response of a current-carrying type-II supercon ducting Corbino disk subjected to a perpendicular applied magnetic field. F or a disk containing remanent flux in zero field, our theory predicts that applying a radial transport current or raising the temperature at fixed cur rent will cause the magnetic flux to be expelled from the sample. For a dis k initially containing no magnetic flux but carrying a radial current, we f ind that as a perpendicular magnetic field is applied, magnetic-flux penetr ation occurs in three stages: (i) the magnetic flux gradually penetrates fr om 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 resi stive because the radial current density there exceeds the depinning critic al current density J(c), and (iii) magnetic flux continues to enter the dis k, while persistent azimuthal currents flow in an outer annular region wher e the net current density is equal to J(c). We also calculate the behavior of a current-carrying Corbino disk subjected to an ac magnetic field.