Magnetic shielding mechanism and structure design of composites at low frequency: A review

The ultra-low magnetic field environment is essential for the research of fundamental physics and further application of biomedicine and space exploration etc. The single material structure is hard to meet the increasing demand for better shielding performances, whereas the composite shows great potential in addressing this problem. However, the state of art summary about magnetic shielding of composites, especially at low frequencies is insufficient. This review first introduces the magnetic shielding mechanism and the theoretical model of the shielding factor. The calculation method of permeability and the importance of accurate hysteresis properties characterization of magnetic composites are systematically discussed. Subsequently, the current status of magnetic shielding investigation on composite structures including stacked, coating, and foam forms is generalized. Emerging strategies for composite materials to further enhance shielding performances using the synergistic effect of structural and material properties are described. Finally, the challenges faced by composite materials in structural design and mechanism exploration of magnetic shielding are presented, providing a fresh perspective for its development.