Static friction as a function of waiting time probed by dynamics of driven vortices in Static friction as a function of waiting time probed by dynamics of driven vortices in La_(2-x)Sr_xCuO_4 thin films

摘要

In the physics of friction, the clarification of the criteria for the validity of Amontons-Coulomb's law has been a challenge for a long time. Especially, friction phenomena at the microscopic system are complicated and the mechanism of the elementary excitation at interface is not understood well. Therefore, it is important to find the criteria for the validity of Amontons-Coulomb's law in such a microscopic system. To solve this subject, we investigated the dynamics of driven vortices in high-T_c superconductor as the ideal model system of friction. We have been investigated about two representative friction phenomena which cannot be explained by the Amontons-Coulomb's law; the velocity dependence of the kinetic friction force, F_k(v), and the waiting time dependence of the maximum static friction force, F_s(t_w).