Magnetic Vortex Dynamics and I-V Characteristics in Type-II Superconductors

We study the dynamics of flux vortices and I-V characteristics of a type-II superconductor in which the flux-pinning centers are randomly distributed with various contents and applied with a transport current and an external magnetic field. When an external magnetic field and transport current are applied to a superconductor, the vortex dynamics inside the superconductor is very complex. This is especially true if the flux-fixing centers are randomly distributed. We have performed simulations by choosing the transport current through the type-II superconductor in which the first vortex motion is observed and the value of the applied external magnetic field. The simulation results of vortex dynamics inside superconductors are analyzed through electric field profiles and E-t curves. We emphasize here that the electric field profile and total energy have a very close relationship. We found that the change in total energy is the most significant at ω=0.2, in terms of the content of the flux-pinning centers distributed inside the superconductor. This indicates that the distribution of flux-pinning centers plays a very large role in the properties of the type-II superconductor. We also found from our study of the I-V characteristics of superconductors that when a superconductor transitions from a superconducting state to a normal conducting state, the I-V characteristics are linearized, especially as the content of the flux-pinning centers increases faster.