Investigation of Magnetic End Effects in Amorphous Wires and Ribbons and Simulation of the Resulting Magnetoimpedance

The existing experimental results have shown that the magnetic characteristics of amorphous wires in different length or in different positions at the end are significantly varied. To study the end effect, the magnetic field distribution at the end of amorphous ribbon of infinite-length and finite-width is analyzed by means of conformal mapping. Because the internal magnetic field intensity of the amorphous ribbon is impossible to exceed that of the external, the model of three magnetic zones is proposed, which consists of the magnetic uniform zone in the middle, the magnetic in-zone and out-zone at the two ends. And the formula for calculating the critical length of magnetic end effect is derived. Due to the great difficulty in obtaining the analytic solution of the end magnetic field of amorphous wire, the assumption in the distribution of magnetic charges and the numerical computation method are applied to obtain the magnetic field distributing form at the end of amorphous wire. The three-zone model is also suitable for the distribution of the amorphous wire and its critical length formula of the magnetic end effect can be deduced. Considering the magnetic end effect, a simple simulation modeling method to study the magnetoimpedance of amorphous wires and ribbons is presented based on the fitting magnetization curve and the local magnetization analysis, which can well explain the existing experimental phenomena.