Neutron Diffraction Insights into the Unconventional Magnetism of NdGaSi

NdGaSi, a rare-earth-based compound from the less explored RGaX family, exhibits anisotropic magnetism and a large anomalous Hall conductivity (1165 Ω⁻¹·cm⁻¹)—unusual for a localized 4f system. Magnetization data show a soft ferromagnetic response along the c-axis, contrasting with its analogue NdAlSi. However, powder neutron diffraction detected no magnetic Bragg peaks down to 4.7 K, suggesting weak long-range order or dominant short-range correlations. Neutron depolarization indicates mesoscopic domain magnetization below the transition temperature ₘ ≈ 14 K. To uncover the magnetic ground state, we propose single-crystal neutron diffraction on the SXD diffractometer. Temperature-dependent measurements will enable the detection of weak magnetic reflections and the determination of spin configuration and symmetry. This study is key to understanding the microscopic origin of NdGaSi’s anisotropic magnetism and anomalous Hall effect and will provide insight into its potential for hosting topological magnetic states.