Structural and magnetic properties of BaFe1-XTiXO3-δ system

Abstract

Abstract: Polycrystalline samples BaFe_1-xTi_xO_3-δ (0 ≤ x ≤ 0.15) have been prepared by the solid-state reaction method and their structural and magnetic properties have been investigated by means of neutron diffraction method and magnetization measurements. At x ≤ 0.025, the samples adopt a triclinic brownmillerite crystal structure with symmetry P2₁/c and demonstrate a long-range antiferromagnetic order at room temperature. Upon Ti doping, the room-temperature ordered magnetic moment of Fe spin gradually decreased from 3.25(5) m_B at x = 0 to 2.15(5) m_B at x = 0.025, indicating a suppression of the long-range antiferromagnetic phase. At x = 0.05, it was observed a structural phase transition from the initial triclinic brownmillerite structure to a hexagonal 6H one with symmetry P6₃/mmc. For the hexagonal phase, Ti doping was found to cause a full suppression of the AFM long-range helical order as previously reported for the undoped 6H BaFeO_3-δ and transformed it into a cluster glass state.

Keywords: Neutron diffraction, crystal structure, magnetic property, multiferroics.