A novel method for measuring the effective permeability of a μ-metal magnetic shield

Abstract

For making better use of a μ-metal magnetic shield, an important precondition is to obtain its effective permeability. However, when μ-metal materials are processed into the magnetic shield, the effective permeability becomes difficult to be measured. We find that though the magnetic shield can reduce the outside magnetic interference, it will enhance the internal generated magnetic field, and the enhancement degree is related to the effective permeability of the magnetic shield. Based on this finding, a method to measure the effective permeability of a μ-metal magnetic shield is proposed, which can avoid the constraint of measuring precision for the existing methods that the magnetic shield is not a measuring whole. By analyzing the influence of the magnetic shield on the magnetic field in the shielded region, and comparing this influence obtained by experiment and simulation, this method can realize the measurement of the effective permeability of a μ-metal magnetic shield.