Advanced Materials for Electromagnetic Shielding
by Maciej Jaroszewski, Sabu Thomas, Ajay V. Rane
6Magnetic Field Shielding
Qiang Zhang
Department of Materials Science, Key Laboratory of Advanced Structure‐Function Integrated Materials and Green Manufacturing Technology, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, P. R. China
6.1 Introduction
A magnetic field exists in any place of the Earth. It includes the weak geomagnetic field and the high intensity field generated by high power equipment, electronic devices, and power transmissions. The magnetic field will disturb sensitive electrical and high‐accuracy electronic sensors [1], or even cause possible health hazards for humans. It has been reported that cancer mortality grows slightly with increasing magnetic field exposure [2]. Therefore, magnetic field shielding, especially for the low frequency and static magnetic field, has become a serious problem. It is necessary to build magnetic shields either for the sources or for objects that should be protected.
On the one hand, equipment that is sensitive to magnetic fields requires protection from external magnetic fields, such as the geomagnetic field, to ensure optimal operation. The intensity of the geomagnetic field is very low, with a magnitude ranging from 2.5 × 10−5 to 6.5 × 10−5 T at the Earth's surface [3]. For sensitive electrical and high‐accuracy electronic sensors, their tolerance to the environmental magnetic field is limited, and even a field like the geomagnetic field may cause disturbance and disablement. Consequently, ...