Magnetic structure, magnetic interactions and metamagnetism in terbium iron borate TbFe3(BO3)4: a neutron diffraction and magnetization study

Magnetization, susceptibility and neutron scattering measurements were performed on the terbium iron borate TbFe 3 (BO 3 ) 4 . Structural and magnetic phase transitions were obtained as a function of external magnetic field and temperature. A metamagnetic transition of the terbium spins and a spin-flop transition of the iron sublattice are obtained at an external magnetic field 35 kOe< H t <60 kOe. The values of the effective exchange H E and the anisotropy H A fields are evaluated. Temperature dependent neutron diffraction studies reveal the magnetic structure of TbFe 3 (BO 3 ) 4 and the thermal evolution of the two magnetic sublattices. An antiferromagnetic coupling along the helicoidal chains of Fe atoms sets in at 40 K with a propagation vector . The magnetic ordering of the Tb sublattice sets in at the same temperature and leads to an anti-parallel alignment of the Fe and Tb moments within the a–b -planes with μ Fe = 4.4 µ B and μ Tb = 8.6 µ B at 2 K.