Stacking faults in Co-based alloy grains in a Co100−xMx (M: Cr, Mo or W) film were evaluated by means of in-plane X-ray diffraction. Moreover, the correlation between stacking faults and uniaxial magnetocrystalline anisotropy Ku was considered in connection with the spin-orbit interaction. The ratio of the integrated intensities of the (10•0) to (11•0) diffractions corrected by Lorentz and atomic scattering factors was proposed as an index for stacking faults in hexagonal close-packed films with a c-plane sheet texture. This ratio was equal to 0.25 for perfect hexagonal close-packed stacking, while it was 0 for perfect face-centred cubic specific stacking. It has a one-to-one correspondence with the probability of -A-B-C- atomic-layer stacking Pfcc. Using this index, pure sputtered Co films were found to have a Pfcc of 10%. The addition of only 5at% of Mo or W into the Co grains reduced Pfcc to 2%. Ku was found to increase with the addition of material (e.g., Ku was 4.0 x 106ergs/cm3 for 5at%Mo), although the atomic magnetic moment of Co decreased monotonously. A Pfcc of 10% was found to lower Ku in a pure Co film by more than a factor of 2 when the spin-orbit interaction was taken into account.

Uniaxial Magnetocrystalline Anisotropy for c-Plane Oriented Co100−xMx (M: Cr, Mo, W) Film with Stacking Faults. S.Hinata, R.Yanagisawa, S.Saito, M.Takahashi: Journal of Applied Physics, 2009, 105[7], 07B718