Analysis of a Fluxgate Incorporating Demagnetization Field

Abstract

It is not accurate incorporating the demagnetizing field by the average demagnetizing factor due to the time variations of the permeability and the dependence of the demagnetization field on the permeability of the sample material. Especially when the magnetic field changes with the position greatly, the local demagnetizing tensor can't be simplified as a number D, thus the internal field H can't be described by demagnetization coefficient D. Although the transient magnetic simulation using the finite-element method can give a correct result, the computation time is relatively too long. Especially for voltage source excitation, a number of trial transient magnetic simulations have to be performed to find the suitable number of winding, the voltage supply, and the excitation frequency. To reduce the optimization time, a method was proposed in this work. With our method only one transient magnetic simulation with current source excitation using the finite-element method was needed. Optimization can be performed using HSPICE. Experiment results confirmed the validity of our method.

Modelling and Measurement of Magnetically Soft Nanowire Arrays for Sensor Applications

“…where A w /A air is array density. We have already shown by FEM simulations and verified by measurement that for small wire arrays the real values of the amplification factor are much lower [50].…”

“…where B mean is the average value of magnetic flux density within the wire volume that was inserted into the homogeneous field with intensity H 0 . The relation between the magnetometric demagnetization factor D and apparent permeability is described by the formula [50]…”