Sweep rate dependence of magnetic hysteresis loops and peak effect in high-T_c superconductors

摘要

The origin of the effect in QMG-processed YBCOwas investigated using the sweep rate dependence of magnetichysteresis loops. A numerical analysis of magnetic hysteresis loopsdemonstrated that electric field E versus current density Jcharacteristics than the conventional Bean one. The pinningpotential energy can be obtained from the slope of the log E versuslog J plot accurately. By analysing the experimental data with thepeak effect using the Mawatari method, it was found that thepinning potential energy and the critical current density have thepeak values at different magnetic fields. This anomalousphenomenon incidental to the peak values at different magneticfields. This anomalous phenomenon incidental to the peak effectcan be explained by the Klein model which is based on the conceptof the field-induced flux pinning.