A Magnetic Susceptibility Measurement System Based on a Single-Axis Atomic Magnetometer

Accurate measurement of magnetic susceptibility plays a pivotal role in diverse scientific disciplines, ranging from material characterization to geophysical exploration. Superconducting quantum interference devices (SQUIDs) have long been regarded as the gold standard for magnetic susceptibility measurements. However, their reliance on cryogenic temperatures and complex setups imposes significant limitations. In this study, we used a single-axis spin-exchange relaxation-free (SERF) atomic magnetometer to measure magnetic susceptibility. We propose a new measurement method that resolves the inherent contradiction between the strong magnetic field and the zero-magnetic-field environment required by the SERF state in susceptibility measurements. The article provides a detailed exposition of the instrument's principles, design, fabrication, and testing results. The achieved measured magnetic moment sensitivity is ${2} \times {10}^{-{6}}$ emu, while the coil system can realize a maximum theoretical sensitivity of ${1} \times {10}^{-{7}}$ emu. In addition, we conducted tests on actual samples and compared the results with those obtained using SQUIDs. This work demonstrates the potential of SERF atomic magnetometers in achieving low-cost, high-sensitivity measurements of magnetic susceptibility.