Initial permeability of amorphous multilayered films

Permeability of amorphous single and multilayered films was studied. A very small anisotropy was obtained by annealing the samples above the Curie temperature followed by rapid cooling. Initial permeability higher then 10000 was obtained. As the multilayered structure becomes finer the domain structure becomes simpler with higher permeability and better frequency characteristics. In the finest structure where thickness of a magnetic layer is 1000 Å wall coercivity increased and permeability became lower. But the finest structure exhibited little deterioration of permeability at high frequencies.