The influence of surface treatment on AC loss in melt-processed quasi-singl
e crystal HTS was investigated with resonance oscillations technique. We ha
ve found that amplitude dependencies of AC loss on magnetic field amplitude
become rather complicated after surface polishing. The experimental data s
how well-distinguished dynamic crossover from absence of barrier at low rat
es of field variation to its appearence at higher rates. An explanation of
such a dynamic surface barrier appearance based on consideration of along s
urface vortex propagation was suggested. (C) 2000 Elsevier Science B.V. All
rights reserved.