Magnetic structure, magnetic interactions and metamagnetism in terbium iron borateTbFe3(BO3)4: a neutron diffraction and magnetization study

Abstract

Magnetization, susceptibility and neutron scattering measurements were performed on the terbium ironborate TbFe3(BO3)4. Structural and magnetic phase transitions were obtained as a function of externalmagnetic field and temperature. A metamagnetic transition of the terbium spins and aspin-flop transition of the iron sublattice are obtained at an external magnetic field35 kOe<Ht<60 kOe. The values ofthe effective exchange HE and the anisotropy HA fields are evaluated. Temperature dependent neutron diffraction studies reveal the magnetic structureof TbFe3(BO3)4 and the thermal evolution of the two magnetic sublattices. An antiferromagnetic couplingalong 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 temperatureand leads to an anti-parallel alignment of the Fe and Tb moments within thea–b-planeswith μFe = 4.4 µB and μTb = 8.6 µB at 2 K.