A High-Sensitivity Magnetic Moment Measurement System for Large Samples Based on a Single-Axis Atomic Magnetometer

The measurement of remanent magnetic moments in rocks is essential for the study of paleomagnetism and rock magnetism. However, it is challenging to achieve high sensitivity nondestructive detection of residual magnetic moments in large samples. Using superconducting quantum interference devices (SQUIDs)-based measurement systems for large-sample measurements necessitates sample sampling, potentially causing sample damage, and is associated with the high cost of the equipment. Using coils, magnetic flux gates, and similar methods for measurement also struggles to provide highly sensitive magnetic moment information. To address the challenge of low-cost, high-sensitivity, and wide-range magnetic moment measurements, this article presents a prototype residual magnetic moment measurement system (MMMS) based on a compact single-axis spin-exchange relaxation-free (SERF) atomic magnetometer (AM). The article begins by elucidating the fundamental principles of using an AM for magnetic moment measurements. It then provides a detailed account of the instrument’s design, fabrication, and the results of various performance tests. In the end, a measurement system with a range of
$1 \times 10^{-11}\sim 1.28 \times 10^{-5} \mathrm {Am}^{2}$
is achieved. In terms of theoretical sensitivity, it is comparable to SQUID measurement systems. We also propose a rapid method for measuring the magnetic moments of large samples and demonstrate its application on actual basalt samples. This work underscores the potential of a compact single-axis SERF AM for cost-effective and highly sensitive detection of the remanent magnetic moments of rocks.