Investigation of relaxation phenomena in high-temperature superconductors HoBa2Cu3O7-δ at the action of pulsed magnetic fields

A mechanical method to investigate the stimulated Abrikosov vortex dynamics in superconductors has been used. We found out that pulsed magnetic fields change the path of relaxation processes taking place in vortex matter. The study of the influence of magnetic pulses differing in their durations and amplitudes on the vortex system of the isotropic high-temperature superconductor system HoBa2Cu3O7-δ showed the presence of a threshold phenomena. Short duration pulses do not change the path of relaxation processes taking place in vortex matter. When the duration of pulses exceeds some critical value (threshold), then their influence changes the path of relaxation process which is revealed by a stepwise change of the relaxing mechanical moment τrel. These investigations showed that the time for formatting of the Abrikosov vortex lattice in HoBa2Cu3O7-δ is of the order of 20 μs which exceeds by one order of magnitude the time necessary for formation of a single vortex observed in type II superconductors