Magnetic Field Shielding

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, or even cause possible health hazards for humans. 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. On the other hand, magnetic shielding is important in environmental protection and human health. This chapter describes the fundamental principles of a magnetic field and magnetic shielding. It reviews the standard shielding materials, such as metallic and ferromagnetic materials, ferrite materials, superconducting materials, amorphous, and nanocrystalline alloys.