Magnetization Dynamics Control for Noise Reduction in Fluxgate Sensors
Chunyang Mu, Zengkun Tian, Lining Pan, Haoran Ma, Mengran Su, Aina He, Weiming Yang, Haishun Liu, Yaqiang Dong, Qikui Man, Baogen Shen, Jiawei LiABSTRACT
Fluxgate sensors are indispensable for the detection of weak magnetic fields. However, their noise performance remains constrained by an incomplete understanding of the interplay between the high‐frequency magnetization dynamics of the core material and the overall sensor behavior. Unlike conventional quasi‐static evaluation methods, this study identifies the high‐frequency magnetization squareness ratio as a pivotal factor in noise suppression. By implementing optimized isothermal annealing of Co‐based amorphous wires, we achieved precise control over their high‐frequency magnetization characteristics, thereby reducing the sensor noise to 20 pT Hz −1/2 @1 Hz. By using a multi‐scale physical modeling approach, we elucidate the underlying mechanism and establish a clear correlation between microstructural evolution, high‐frequency domain dynamics, and magnetic noise reduction. These findings provide a new framework for material selection and device design in the development of ultra‐low noise fluxgate sensors.