Domain wall calculations for SmCo5

The structure of domain walls may be studied theoretically by considering the wall either to be a continuous magnetization distribution (micromagnetic-type approach) or a discrete moment distribution. It is shown that the discrete moment approach becomes necessary in materials of high magnetocrystalline continuous such as SmCo5, where the domain walls are only of the order of 10-20 atomic distances wide. The structure of such walls is found to be very sensitive to short range variations in exchange and anisotropy and the presence of an anomalous exchange interaction between two spins produces pinning fields which are of the same order as values of coercivity in SmCo5. It is concluded that exchange anomalies may play an important role in domain wall pinning in the rare-earth/cobalt materials and that further information on the exchange mechanisms could help to explain their high coercivities.