EFFECT OF SURFACE-BARRIER ON THE VORTEX RELAXATION IN HIGH-TEMPERATURE SUPERCONDUCTORS

The rate of vortex relaxation over the surface barrier in HTSC is foun d. For the flux edt over the surface barrier the magnetization M depen ds logarithmically on time whereas for the case of flux entry M is a s trongly non-linear function of In t. The initial relaxation rate, dM/d ln t, Proves to be much larger for flux entry than for exit in contra st to the case of the conventional bulk creep (where these rates are a pproximately equal). The competitive interplay between such a surface relaxation and the usual bulk one, which results in a crossover in the M(In t) curve, is duscussed.