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

Abstract

Magnetization, susceptibility and neutron scattering measurements were performed on the terbium iron borate TbFe3(BO3)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<Ht<60 kOe. The values of the effective exchange HE and the anisotropy HA fields are evaluated. Temperature dependent neutron diffraction studies reveal the magnetic structure of TbFe3(BO3)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 μFe = 4.4 µB and μTb = 8.6 µB at 2 K.