Design of a MEMS Heating Film with Octagonal Multipole Magnetic Moment for Miniaturized SERF Magnetometers

Spin-Exchange Relaxation-Free (SERF) atomic magnetometers exhibit exceptionally high sensitivity. However, their performance is seriously influenced by magnetic interference and non-uniformity temperature induced by electrical heating of the vapor cell. Consequently, designing a heating device with minimized magnetic interference and thermal uniformity is critical for enhancing sensor sensitivity. To achieve a trade-off between magnetic suppression and thermal homogeneity, this paper proposes a micro-electro-mechanical system (MEMS) heating coil design method with an octagonal multipole magnetic moment for miniaturized SERF magnetometers. First, a magnetic field model of the coil is established, alongside constraints for thermal distribution uniformity. Subsequently, a multi-objective nonlinear optimization framework based on the Non-dominated Sorting Genetic Algorithm II (NSGA-II) algorithm is employed to optimize coil geometric parameters. Finite Element Analysis (FEA) validates the effectiveness of the proposed structure. The results indicate that, compared to the traditional equid-width square coil, the optimized octagonal coil design reduces the average temperature deviation of the working surface by 16.4 % to 0.188° C, while simultaneously reducing the average magnetic flux density by 1 2.7\% to 4 2. 7 ∼ p T / m A.