  Oblique/normal sequential deposition technique is used to create Co based
unique multilayer structure [Co-oblique(4.4nm)/Co-normal (4.2 nm)]x10, where
each Co-oblique layer is deposited at an oblique angle of 75deg, to induce
large in-plane uniaxial magnetic anisotropy (UMA). Compared to the previous
ripple, stress and oblique angle deposition (OAD) related studies on Cobalt in
literature, one-order higher UMA with the easy axis of magnetization along the
projection of the tilted nano-columns in the multilayer plane is observed. The
multilayer retains magnetic anisotropy even after annealing at 450C. The
in-plane UMA in this multilayer is found to be the combination of shape, and
magneto-crystalline anisotropy (MCA) confirmed by the temperature-dependent
grazing incidence small angle X-ray scattering (GISAXS), in situ reflection
high energy electron diffraction (RHEED) and grazing incidence X-ray
diffraction (GIXRD) measurements. The crystalline texturing of hcp Co in the
multilayer minimizes spin-orbit coupling energy along the column direction,
which couples with the shape anisotropy energies and results in preferential
orientation of the easy magnetic axis along the projection of the columns in
the multilayer plane. Reduction in UMA after annealing is attributed to
diffusion/merging of columns and annihilating crystallographic texturing. The
obtained one-order high UMA demonstrates the potential application of the
unique structure engineering technique, which may have far-reaching advantages
in magnetic thin films/multilayers and spintronic devices.
