Numerical simulation of the effect of defects on the magnetization switching in single domain particles with non-uniform magnetization distribution

Summary form only given. The magnetization switching of non-ellipsoidal, small particles is important for future high density magnetic recording on patterned media. The broad distribution of switching fields of particles presents a problem in other applications of small particle systems, like MRAM arrays, or magnetic MEMS. Experiments on a model system of single crystal garnet particles showed that the measured statistical distribution of switching fields has a surprisingly large standard deviation, H/sub sw/= 285/spl plusmn/85 Oe. The overall reduction of the switching field, relative to the anisotropy field of 2 kOe, is related to the non-uniform magnetization distribution, due to the shape of the particles. Detailed experimental investigations revealed that very weak crystalline defects of these extraordinary high quality epitaxial garnet crystals are responsible for the broad distribution of the switching fields. This work presents micromagnetic simulation of the measured switching process for particles, with and without defects, to prove the feasibility of numerical simulation when direct experimental data are not available.