Induced anisotropy of amorphous CoFeSiB and CoNbZr magnetic materials

Uniaxial anisotropy induced by magnetic annealing was studied on amorphous CoFeSiB and CoNbZr layers. The kinetics of inducing the anisotropy is slowed down by a preanneal at 400°C. This effect is much stronger for CoNbZr than for CoFeSiB. An addition of 2% transition metal (TM) atoms does not influence the kinetics after preannealing appreciably. Simultaneously with inducing anisotropy magnetic annealing changes the magnetostriction. Two effects determine the anisotropy, orientation of pairs of different magnetic atoms and a contribution which also occurs in alloys with a single magnetic atom. The latter contribution is independent of type and size of the non-magnetic atom(s) and is attributed to Co - clusters.