Magnetization Measurements of 1/3 plateau in Kagome Antiferromagnet In-Kapellasite Using Compact Faraday-Force Magnetometer

Kagome-lattice antiferromagnets have attracted significant attention as ideal platforms for studying strong geometric frustration and quantum magnetism. In particular, S = 1/2 systems exhibit pronounced quantum fluctuations, giving rise to exotic states such as quantum spin liquids, magnetization plateaus, and localized magnons. Among them, InCu6(OH)6Cl3 (In-Kapellasite) and ScCu3(OH)6Cl3 (Sc-Kapellasite) are recently developed S = 1/2 kagome antiferromagnets that offer opportunities to explore such field-induced quantum phenomena. In particular, a 1/3 magnetization plateau has been reported in In-Kapellasite under magnetic fields of 7–14 T, whereas its microscopic origin and temperature evolution remain open questions[1]. To investigate magnetic properties in the plateau states in these materials, we have developed a compact Faraday-type magnetometer incorporating a miniature superconducting Helmholtz coil that locally generates a field gradient near the sample, combined with a standard solenoid-type superconducting magnet. This setup enables high-sensitivity magnetization measurements down to 50 mK and up to ±10 T. We report magnetization data for both In- and Sc-Kapellasites over a wide temperature. The low-temperature measurements are expected to provide new insights into the mechanism and quantum nature of the magnetization plateau in kagome quantum magnets.