Soft Magnetic Properties of a-CoNbTi/SiO2 Layered Films

The effects of multilayering on the soft magnetic characteristics of a-CoNbTi/SiO₂ amorphous alloy layered films were studied. H_c of a single-layer film increased rapidly as film thickness decreased from 300 Å, but H_c decreased by multilayering a-CoNbTi with SiO₂ thin layers. Favorable ac characteristics were, however, not obtained when the magnetization measurement direction was parallel to the internal magnetization. Thus, a perpendicular field annealing was needed. The magnetic layers were less than 2500 Å thick, the thinner the SiO₂ and magnetic layers, the higher was the maximum permeability.