Initial results of a micromagnetic study on elongated iron particles are presented. A numerical micromagnetic model is utilized to compute the magnetization configurations and switching fields for both the homogeneous metal particle and the inhomogeneous passivated particle from first principles. The volume of the passivated particle is divided into a metallic core and a passivated shell with significantly reduced magnetic‐moment density. The calculations show that the topology of the magnetization configurations is similar to those of homogeneous &ggr;‐Fe2O3particles. The switching field is higher for the passivated particles as compared to the homogeneous particle depending on the exchange interaction in the passivation layer. The enhancement of the switching field is explained in terms of reduced torques and reduced demagnetization at the passivated particle ends.