Micromagnetic modeling analysis and magnetic force microscopy studies were performed in order to characterize the magnetization configuration and magnetic switching behavior in two types, PM I and PM II, of submicron Pac-man-shaped Ni80 Fe20 magnetic elements. It was found that a slight variation in the shape of the elements has a striking influence on the internal magnetic structures and switching field distribution. In particular, the vortex-formation driven switching is replaced by quasicoherent reversal by removing the central core part at the center of element. The sensitive dependence of remanent magnetic configuration and switching behavior on sample geometry is discussed in terms of the competition between the exchange and demagnetizing energy terms. © 2005 American Institute of Physics.