Shima et al. [100] have measured coercivities of up to 40 kOe (3200 kA/m) for FePt thin films with strongly faceted islands (cf. Fig. 8.1), which agree well with our simulations. In very small FePt nanoparticles of approximately 20 nm diameter Bian et al. [101] have found regions with different easy axes (as shown in Fig. 8.2) and measured coercivities of 4.4 kA/m. Our simulations have shown a similar reduction in coercivity depending on the particle size and distribution of easy axes. However, close cooperation with experimental groups will be necessary to model the microstructure of the thin films and nanoparticles properly and use appropriate material parameters.