Minimizing magnetic fields of the low-noise MnZn ferrite magnetic shield for atomic magnetometer

作者：Ke Yang, Jixi Lu, Zixuan Wang, Bowen Sun, Yanning Ma, Yaoguo Wang, Bangcheng Han · 发表于：Journal of Physics D Applied Physics · 年份：2021 · DOI：10.1088/1361-6463/ac2b67 · 被引用次数：35 · 研究领域：Atomic and Subatomic Physics Research、Advanced MRI Techniques and Applications、Advanced Frequency and Time Standards

Abstract Several modern precision measurements require a low-noise magnetic shield composed of a MnZn ferrite shield and a multilayer µ-metal shield. However, the residual magnetic field and gradient reduce the performance of the low-noise magnetic shield. An appropriate demagnetization operation is crucial for obtaining a lower residual magnetic field and gradient. This study proposes an improved demagnetization scheme in which the toroidal coil and the solenoidal coil are employed simultaneously, while the ferrite and µ-metal shield layers are wound separately. This allows for a residual field below 0.6 nT and a gradient lower than 0.5 nT cm−1 to be obtained along all three axes within ±20 mm at the center, which is significantly lower than the results published in previous studies. The low-noise magnetic shield used in this study composed of a MnZn ferrite shield with an inner diameter of 112 mm, an outer diameter of 140 mm, and a height of 225 mm, and a five-layer µ-metal shield. This study considerably improves the performance of the low-noise magnetic shields. The proposed scheme can increase the sensitivity of the spin-exchange-relaxation-free atomic magnetometer by approximately 1 fT Hz-1/2. This study can help apply the low-noise magnetic shield in various fields more conveniently, such as low-field nuclear magnetic resonance detection, atomic gyroscope, and in cutting-edge physics research.