Effects of Electrolytic Current Density on Structural, Magnetic Properties and GMI Behavior in Electrodeposited Bilayer FeNi/Cu Composite Wires

In this article, a systematic study has been performed on structural, magnetic properties and the GMI effect in electrodeposited FeNi/Cu composite wires in the range of current density from j =15.9 mA/cm 2 to 79.5 mA/cm 2 . Our obtained results reveal a correlation between the structure, magnetic softness, and GMI behavior in prepared wires. Among the samples investigated, the softest magnetic property (lowest coercivity) was found for the wire-sample plated at j =47.7 mA/cm 2 , which arises from the smallest nanograin size. This results in the largest values of GMI ratio and its sensitivity of this sample, which is ascribed to the optimized domain structure with a well-defined circular anisotropy. It is worthy to note that the maximum GMI ratio and the field sensitivity reached the highest values of 90 % and 7 %/Oe for at a measuring frequency of 5 MHz. This result is very promising for developing high-performance GMI-based sensors applications. Our finding demonstrates that the changes in the surface morphology and the microstructure of prepared wires has led to modification of the surface magnetic properties, and hence GMI effect.