Structural study of the plastic deformation in epitaxial Fe/MgO(001) thin films

The "atomic saw" method has been applied to cut epitaxial Fe thin films deposited on (0 0 1)MgO substrates into stripes. Previous magneto-optical results performed on such samples have evidenced a strong magnetic anisotropy with the easy magnetic axis perpendicular to the stripes. We report on microstructural studies performed by atomic force microscopy and transmission electron microscopy on deformed samples. This work shows that the plastic deformation induces a non-homogeneous anisotropic relaxation of the strained Fe film. The magnetoelastic effect associated with this relaxation is then assumed to be responsible for the uniaxial magnetic anisotropy.