Institute of Large-scale Scientific Facility and Centre for Zero Magnetic Field Science, Beihang University, Beijing 100191, China and Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, Zhejiang, China
National Institute of Extremely-Weak Magnetic Field Infrastructure, Hangzhou 310051, Zhejiang, China
*Also at Hefei National Laboratory, Hefei 230088, China.