Spin-amplification SERF atomic magnetometer based on direct feedback Yujian Ma, Ziqi Yuan, Shudong Lin, Yueyang Zhai and Junjian Tang EPJ Quantum Technol., 12 1 (2025) 70 Published online: 11 June 2025 DOI: 10.1140/epjqt/s40507-025-00378-7