Abstract

Giant magnetoimpedance (GMI) was studied in electrodeposited Co/Cu/Co-coated Ag wires with variations in the axial dc magnetic field (0-2 kOe), frequency of ac driving current (1 kHz-100 MHz), thickness of each layer (1.0-25.0 νm) and diameter of the Ag core (47.7 and 120.0 νm). With increasing thickness of coated layers and Ag cores, the maximum GMI ratio increased but the characteristic frequency decreased. Unlike Co-coated Ag wires, the frequency-dependent GMI curves of these multilayered wires were broadened and asymmetric. The GMI behaviours were explained in terms of the distribution of current density and current flow in the coated wires obtained from the finite element method simulation program. © 2007 IOP Publishing Ltd.