Ferromagnetic spin fluctuations in the kagome metal Sc₃Mn₃Al₇Si₅ revealed by ²⁷Al nuclear magnetic resonance measurement

Sc₃Mn₃Al₇Si₅ (SMAS) with a hexagonal structure (space group P63/mmc) has been reported to be one of the rare metallic systems with Mn ions forming the kagome lattice. Magnetic susceptibility, specific heat, and neutron diffraction measurements show no long-range magnetic order down to 1.8 K. To investigate the magnetic and electronic states of SMAS from a microscopic point of view, we have carried out ²⁷Al nuclear magnetic resonance (NMR) measurements in the temperature region between 1.5 K and 300 K. From our analysis using the NMR results of the temperature dependences of the NMR spectrum and the nuclear spin-lattice relaxation time T₁, ferromagnetic spin fluctuations were found to develop with decreasing temperatures. This is consistent with the recent report of ²⁷Al NMR measurements. In the talk, I will also report our new data of ⁵⁵Mn NMR in addition to the ²⁷Al NMR results and discuss the peculiar metallic state of the compound.