On the synthesis and cation distribution of aluminum-substituted spinel-related lithium ferrite

Spinel-related Al-substituted Li0.5Fe2.5O4 has been synthesized by sintering a mixture of Al-substituted corundum-related α-Fe2O3 and Li2CO3 at 700 °C which is ca. 450-500 °C lower than the temperatures normally used to prepare the material by conventional ceramic methods. The cation distribution in the material was investigated with X-ray diffraction, Mössbauer spectroscopy and magnetic measurements. Rietveld refinement of the X-ray diffraction data shows the Al3+ ions to substitute for both Fe3+ and Li+ ions on octahedral B-sites while the displaced Li+ ions substitute for Fe3+ ones at tetrahedral A-sites. This structural model is consistent with Mössbauer and magnetic data.