Modeling and calculation of magnetic noise in nanocrystalline magnetic shielding barrel considering anisotropy and stress effects

Nanocrystalline alloys provide a low magnetic noise environment for spin-exchange relaxation-free (SERF) magnetic field measurement devices. However, the anisotropy of nanocrystalline significantly impacts their permeability and conductivity. Additionally, nanocrystalline strips on magnetic shielding barrel (MSB) increase magnetic noise due to bending stress. Therefore, this paper proposes an analytical model for magnetic noise calculation considering the anisotropy and bending stress of the nanocrystalline MSB. First, the magnetic noise computation model of the nanocrystalline MSB considering anisotropy, is established. Then, the bending stresses of the nanocrystalline ribbons with different curvatures are quantitatively modeled. The nanocrystalline loss under different bending stresses is separated by constructing a stress-dependent dynamic Jiles-Atherton (SDDJA) model. The magnetic noise of nanocrystalline MSB is calculated, and results show that the bending stress in the nanocrystalline MSB is positively correlated with hysteresis loss noise. The difference in average magnetic noises (1–100 Hz) of the nanocrystalline MSB between the experiment and calculation is only 4.17 %, which verifies the proposed method. This research can improve the accuracy of magnetic noise analysis and be the design benchmark for magnetic noise suppression.