Influence of core-wire on giant magnetoimpedance effect in electrodeposited composite wires

The effect of non-magnetic core wire diameter and conductivity on giant magnetoimpedance (GMI) in composite wires has been investigated. Microstructure, magnetic and magnetoimpedance (MI) properties of a Permalloy (Ni80Fe20) films electrodeposited on Cu, Ag and Nichrome wires have been investigated. Present results show that the magnitude of MI varies (from 611% to 31%) with both core-wire diameter (0.1 mm to 1.17 mm) and conductivity. Maximum MI (∼700%) and sensitivity (∼40%/Oe) is observed at 50 kHz for the NiFe film deposited on 100 μm Ag wire. The frequency (fmax) at which maximum in MI is observed depends on the effective conductivity of the wire. Further, from the model calculation we have shown that the skin depth (δ) at fmax increases with the increase in core wire diameter of the composite wire and this in turn related to GMI. Therefore, from the present study we conclude that the MI parameters, such as, field sensitivity, MI and fmax can also be tuned by choosing a suitable core-wire. These observations are in agreement with the results obtained from the numerical simulations.