Structure and magnetic anisotropy of epitaxial fcc-Co(110) and hcp-Co(11̄00) films

Fcc-Co(110) and hcp-Co(11̄00) films of 200 Å thickness were grown on MgO(110) and bcc-Cr(211)/MgO(110), respectively, by the molecular beam epitaxy method. Reflection high energy diffraction was used to in situ characterize the crystal structure. Co films grown directly on MgO(110) were pseudomorphic fcc structure. Twofold symmetrical hcp-Co(11̄00) films on top of the bcc-Cr(211)/MgO(110) were grown and confirmed. The magneto-optical Kerr effect (MOKE) was used to investigate the magnetic anisotropy of these films. The magnetization of these samples was found to be in-plane. The magnetization of fcc-Co films has cubic symmetry with texture induced uniaxial anisotropy. For hcp-Co(11̄00)/bcc-Cr(211) bilayer films, the magnetization was strongly anisotropic, but independent of the thickness of the Cr layer.