  A generalized phenomenological model for the critical state of type-II
superconductors with magnetic field parallel to the superconducting plate is
proposed. This model considers the global magnetization including both the
equilibrium magnetization from surface screening current and the
non-equilibrium magnetization from bulk pinning in a self-consistent way. Our
model can be used to simulate the magnetization-hysteresis-loops (MHLs) and
flux penetrating process of different type-II superconductors, from low- to
high-kappa values. Here we take an optimally doped Ba0.6K0.4Fe2As2 single
crystal as a testing example. The model can fit the data quite well and several
important parameters can be extracted from the fitting. Thus, the model can be
extended to a general case for studying the magnetization and flux penetration
in other type-II superconductors.
