Soft magnetic properties of Permalloy multilayered films with ceramic intermediate layers

Multilayer thin films of Permalloy with SiO₂, Si₃ N₄, Al₂O₃, or AlN as a ceramic intermediate layer were prepared by rf magnetron sputtering. The effects of intermediate layer materials on the soft magnetic properties, internal stress, and microstructure of multilayer thin films with various Permalloy thickness were investigated. Effective permeability μ_eff, coercive force H_c, and internal stress σ of multilayers with a fixed intermediate layer (20 Å), and a thickness of the permalloy layer, varying from 200 to 5000 Å (number of magnetic layers from 50 down to 2) were measured. Multilayered structures with ceramic intermediate layer thickness of 20 Å and Permalloy layer thickness of less than 500 Å had the lowest coercive force and the highest effective permeability