Origin of uniaxial anisotropy of Fe(001) films epitaxially grown on Pd(001)/Cu(001)/Si(001)

Abstract Fe(0 0 1) films were epitaxially grown on Pd(0 0 1)/Cu(0 0 1)/Si(0 0 1) substrates and uniaxial anisotropy was analyzed by torque curves. The origin of uniaxial anisotropy was revealed to be an orthorhombic deformation of Fe layer and the deformation was beyond an elastic limit. Because of a very large strain in the films, FCC γ-Fe was thought to form on the column boundary in the top layer of the film, which was confirmed in the cross-sectional TEM analysis. This FCC phase can play a role in the orthorhombic deformation.