Magnetic Property Enhancement of Co0.85W0.15 Magnetic Films by Addition of Vanadium in Ru Buffer Layer

High magnetic anisotropy energy (MAE) is desirable for perpendicular magnetic recording. In order to improve the MAE, a trial of crystal deformation induced by changes of buffer layer compositions was taken. The Co0.85W0.15 magnetic thin films were deposited at 300 °C on RuV buffer layers by DC magnetron sputtering, with 15%V introduced into Ru films. The elaborate crystal structures of the films were examined by X-ray diffraction (XRD). With the results of XRD measurements, the crystal structure, the epitaxial relationship, the lattice parameters, the mosaic spread of the c-axis, the volume ratio of fcc to hcp phases and the stacking fault densities were determined. The correlation of crystal structure and MAE was investigated for Co0.85W0.15/Ru0.85V0.85/MgO(111) films. The experimental results show that the magnetic anisotropy Ku of Co0.85W0.15 films is significantly enhanced with the reduction of c/a, owing to the addition of V in Ru buffer layers. It seems possible to control the magnetic anisotropy of various materials by designing the buffer layer.