Low-temperature magnetic behavior on the triangular lattice in hexagonal Ba3Tb(BO3)3

The hexagonal polymorph of Ba3Tb(BO3)3 contains Tb3+ ions on a quasi-2D triangular lattice, resulting in geometric magnetic frustration. Powder samples of Ba3Tb(BO3)3 have been investigated using specific heat, powder neutron diffraction (PND), inelastic neutron scattering (INS), and muon-spin relaxation spectroscopy (μSR). No long-range magnetic ordering is observed down to the lowest measured temperatures of 75 mK in PND and specific heat data and 1.5 K in the μSR data. Modeling the INS spectrum using a point charge model suggests that the ground state is a singlet with a low-lying doublet on each of the two crystallographically independent Tb3+ sites and that both the Tb ions display weak XY single-ion anisotropy. Published by the American Physical Society 2025