Structural and magnetic characterization of Ti-substituted Li _0.5Fe_2.5O₄ prepared using hydrothermal and solid-state routes

Single-phased spinel-related Ti⁴⁺-substituted Li _0.5Fe_2.5O₄ has been synthesized by heating a mixture of hydrothermally prepared Ti⁴⁺-substituted α-Fe ₂O₃ and Li₂CO₃ at 850°C (12 h). This temperature is ca. 250-350°C lower than those at which the material is conventionally prepared by the ceramic techniques. X-ray diffraction was used to analyze the evolution of the formation process and, in conjunction with Mössbauer and magnetization measurements, to determine the cation distribution of the resulting ferrite. The results imply that the Ti ⁴⁺ ions substitute for Fe³⁺ ones at the octahedral (B) sites whilst the excess Li⁺ ions, required for balancing the charge in the spinel-related structure, replace Fe³⁺ ions at the tetrahedral (A) sites.