  A two-dimensional easy-plane ferromagnetic substrate, interacting with a
dipolar tip which is magnetised perpendicular with respect to the easy plane is
studied numerically by solving the Landau-Lifshitz Gilbert equation. Due to the
symmetry of the dipolar field of the tip, in addition to the collinear
structure a magnetic vortex structure becomes stable. It is robust against
excitations caused by the motion of the tip. We show that for high excitations
the system may perform a transition between the two states. The influence of
domain walls, which may also induce this transition, is examined.
