Induced magnetic anisotropy related to the local atomic order: a study in amorphous Co-Zr and Co-Zr-M thin films

The in-plane uniaxial anisotropy Ku, induced by a magnetic field applied during the deposition, was investigated in amorphous thin films of Co1−xZrx and Co1−x−yZrx My (M=Ti, Nb, and Pt) obtained by rf sputtering. For a given concentration Ku presents a bell-shaped variation as a function of Ar pressure PAr. The critical pressure for which the maximum value of Ku is obtained and the absolute value of (Ku)max changes for the various alloys. These results and the high value of (Ku)max are explained by a model where (Ku)max is related to the local anisotropy via the local structure upon the nonmagnetic metal. (Ku)min is essentially related to a pseudodipolar short-range order.