Ground and excited states of the finite-size Fe chains on Pt

The energy barriers for magnetization reversal of the finite-size Fe chains on Pt(664) surface have been calculated using the geodesic nudged elastic band method. The Dzyaloshinskii-Moriya interaction and the dipole-dipole interaction have been taken into account. It has been found that the ground states of Fe/Pt(664) atomic chains are non-collinear at the ends. The magnetization reversal of short atomic chains occurs without the formation of the domain walls. While the magnetization reversal of the long atomic chains occurs via the formation of the domain walls. The interplay between the magnetic anisotropy energy and the Dzyaloshinskii-Moriya interaction leads to the rotation of the domain wall plane. As a result, the domain walls in Fe/Pt(664) atomic chains are intermediate configurations between Bloch and Néel walls. The dipole-dipole interaction weakly influences the value of the energy barriers and may be neglected. It is shown that the presented results can be explained in the framework of the classical continuous model. The constructed approximate functions correctly describe all features of the ground states and the saddle points. The structure of the domain walls and the dependencies of the energy barriers on the parameters of the model are different from the case of the Co/Pt(664) system investigated recently.