Size effect on magneto-impedance in layered films

The analysis of magneto-impedance (MI) in a sandwich film having an inner c onductive lead and two soft ferromagnetic layers is concerned with the role of the film dimensions in determining the MI ratio. The equation for the A C magnetic field distribution in the sandwich is solved making the assumpti on of a weak skin-effect and a large transverse permeability of the magneti c layers. The flux leakage through the conductive layer results in a consid erable drop in MI ratio if the film width is less than a certain critical v alue depending on the transverse permeability and the layer thickness. This process is similar to that known in inductive recording head, for example, in contributing to head efficiency. (C) 2000 Elsevier Science S.A. All rig hts reserved.