Preparation and magnetic properties of composite wire with double magnetic layers

In this study, Co₆₄P₃₆/Ni₂₇Co₅₉P₁₄/Cu composite wires with double magnetic layers are prepared by electroless deposition, and examined by hysteresis loop and giant magnetoimpedance (GMI). Hysteresis loops of the sample with double magnetic layers show a relatively obvious abrupt magnetization jump when compared a single-layer composite wire. The profile of GMI curves consists of a four-peak feature which indicates that both the magnetic layers have circumferential domain structure. The shift of the knee point on magnetization loops and the peak position on GMI curves show that dipolar interactions play a significant role between the two layers. The value of dipole field H_di decreases with the increase of frequency and thickness of the outer layer in this multi-layer sample by fitting the experimental data. All the results indicate an effective way to study the dipolar interactions among sophisticated composite magnetic wires.