Magneto-impedance effect in NiFe plated wire

The voltage V(t) induced by a sinusoidal drive current traversing a 125-μm-diameter BeCu wire plated with 1 μm NiFe is observed to be a very strong function of axial dc magnetic field. The basic physics of this phenomenon is explained classically in terms of Faraday’s law of induction and Stoner–Wohlfarth magnetization reversal, which yield theoretical predictions that are in good agreement with experiment. For drive current amplitudes of the order of 100 mA, and frequencies of the order of 5 MHz, the field sensitivity dV/dH can be as large as 1 V/Oe (per cm of wire), which offers the potential for application in relatively simple, very high sensitivity magnetic field sensors.