Static friction as a function of waiting time probed by the dynamics of driven vortices in La(2 - x)Sr(x)CuO4 thin films.

We systematically investigated the waiting-time dependence of the maximum static friction force, F(s)(t(w)), using the dynamics of driven vortices in a high-T(c) superconductor as a model system. F(s)(t(w)) was measured in La(2 - x)Sr(x)CuO(4) thin films with different structures, sample sizes and pinning force. We found that F(s)(t(w)) by thermal fluctuation is strongly affected by the pinning strength, the vortex bundle size and the system size. Based on these results, we found crucial conditions to determine the validity of the Amontons-Coulomb's law, and proposed a criterion.