Abstract:
The influence of surface barrier on the third harmonics ac susceptibility sx3d is studied numerically.
The surface barrier is described by a critical current density in surfaces which are higher than the
inside one. The model can act as the critical state one, the flux creep one, or the flux flow one when
temperature sor fieldd changes. The numerical results based on the model are more close to the
popular experimental data probing the harmonics as a function of temperature sor fieldd. Besides, the
surface barrier will lead to new peaks in the real and imaginary parts of the third harmonics, which
are the finger signature of the surface barrier. Comparison of the peaks with those of the real part
of elemental harmonic shows that they are located at the same temperature where dips in x8 caused
by the surface barrier occur, which is in well agreement with experiments.
