  The paper reviews a concept of induced spin-flop domain inside vortices in an
antiferromagnetic superconductor. Such phenomenon may occur when an external
magnetic field is strong enough to flip over magnetic moments in the core of
the vortex from their ground state configuration. The formation of the domain
structure inside vortices modifies the surface energy barrier of the
superconductor. During this process the entrance of the flux is stopped and a
newly created state exhibits perfect shielding. Such behavior should be visible
as a plateau on the dependence of flux density as a function of the external
magnetic field. The end of the plateau determines the critical field, which has
been called the second critical field for flux penetration. Moreover, it is
predicted and described how this phenomenon modifies flux creep in layered
superconductors. The various scenarios of changing the creep regime from
thermal to quantum and vice versa at constant temperature are discussed.
