Vortex dynamics under periodic high- T_c dot arrays embedded in low T_c superconductors

We perform computer simulations for vortex dynamics in high-T_c dot arrays embedded in conventional low T_c superconductors by solving numerically the time-dependent Ginzburg-Landau (TDGL) equation. The high-T _c dot repels vortices, which is in contrast to the anti-dot which works as a strong attractive pinning center. We find that vortex dynamics in the system is much different from that of the anti-dot array systems. For example, vortices can widely distribute outside the dot region when the applied magnetic field H is less than H_c2 of the substrate superconductor (H ^s_c2), while vortices are confined inside very narrow regions between neighboring dots when H>H^s_c2. The complex dynamics is explained in terms of the change of interaction between vortices at H^s_c2.