Modeling and suppression of magnetic noise in P-N composite magnetic shielding devices

Magnetic shielding devices (MSDs) can provide high shielding factors (SFs) and low magnetic noise (MN) environments for fundamental physics research, ultra-weak mind-brain magnetic high-resolution imaging, and material magnetic field analysis. To further suppress and calculate MN, we propose a permalloy-nanocrystalline (P-N) composite shielding structure and establish a quantitative calculation model for MN. Validation experiments conducted on the P-N composite MSD show an average error of 5.32% between theoretical and calculated values within the 3-100 Hz range, confirming the accuracy of the proposed calculation method. Compared to the permalloy MSD, the P-N composite MSD achieves a 29.6% reduction in MN. This research not only establishes a theoretical foundation for the design of low MN MSDs but also offers innovative approaches and technical support for optimizing the application of ultra-weak magnetic field measurement systems.