Anisotropy and coercivity in SmCo5-based compounds

The anisotropy of the RCo5-based compounds depends not only on the local anisotropies but also on exchange interactions of the Sm and Co sublattices. This result allows an accurate determination of the Sm³⁺anisotropy in SmCo5and SmCo3.5Cu1.5; the anisotropic properties of these compounds are discussed in terms of crystal field. The mechanism of domain wall displacement has been studied on a single crystal of SmCo3.5Cu1.5by means of Kerr effect and high field magnetization measurements. Domain walls are trapped in copper rich regions where exchange and anisotropy are lower. Magnetic aftereffect measurements show that in fact the trapping effect is in competition with a kink creation mechanism. On this basis, the thermal variation of the coercive field of the SmCo5-based compound is explained.