THE ORIGIN OF THE INDUCED MAGNETIC-ANISOTROPY IN AMORPHOUS CO-M (M = ZR, NB, TI, PT) THIN-FILMS

The mechanism governing the formation and the magnitude of the induced anisotropy K(u) in CoZrM (M = Zr, Nb, Ti) amorphous films was reinvestigated. The experiments revealed that the variations with concentration of K(u) is incompatible with a pseudo-dipolar-type anisotropy. A new model is proposed with the local anisotropies of octa/icosahedral- and trigonal-type clusters as physical origin of K(u). The respective contributions of each type of cluster to K(u) is determined by the local structure which changes with the pressure of the sputter gas, P(Ar), used during the preparation. The particularities of a-CoZrPt films are pointed out.