Domain wall properties of FePt: From Bloch to linear walls

An investigation of the orientation and temperature dependence of domain wall properties in FeP! is presented. We use a microscopic, atomic model for the magnetic interactions within an effective, classical spin Hamiltonian constructed on the basis of spin density functional theory. We find a significant dependence of the domain wall width and the domain wall energy on the orientation of the wall with respect to the crystal lattice. Investigating the temperature dependence, we demonstrate the existence of elliptical as well as linear domain walls in FePt. The calculation and further analysis of the domain wall free energy results in the evaluation of a thermodynamic exchange stiffness and anisotropy constant.