Investigation of crystal field excitations of the rare-earth based kagome antiferromagnet Sm3BWO9 using inelastic neutron scattering

Rare-earth based frustrated magnets yield a promising route for the search of enigmatic quantum spin liquid (QSL) ground state. QSL materials show a highly entangled state and do not exhibit long range magnetic ordering even at T=0 due to geometric exchange frustration. Recently we have investigated a new rare-earth based distorted kagome lattice Sm3BWO9. The specific-heat data of single crystal and polycrystal show a lambda-type peak at 0.75K, indicating a long magnetic ordering with TN=0.75 K. The 11B nuclear magnetic resonance (NMR) measurements reveal an incommensurate magnetic ordering and proposed two possible magnetic structures. Surprisingly however, our muon spin rotation and relaxation measurements on a polycrystal sample of Sm3BWO9 down to 30 mK on FLAME at PSI do not show any clear sign of long-range magnetic ordering down to 30 mK but reveal persistence of spin fluctuations. To clarify the observed difference between the bulk properties and the μSR results, we have been allocated beamtime on D20/D2B of ILL to investigate the magnetic ground state as well as the ground state spin structure of Sm3BWO9. Here we propose to investigate crystal field excitations on the polycrystal sample of Sm3BWO9 (with 154Sm and 11B isotopes to mitigate the absorption problem) using the thermal neutron time-of-flight spectrometer MERLIN.