Correlating magnetism and structural properties of chemically-lithiated Fe3–δO4

We have investigated the chemical lithiation in 70 nm cubic-shaped magnetite nanoparticles with varying degree of lithiation x = 0, 0.5, 1, 1.5. The induced changes on structure and magnetic properties were investigated with X-ray scattering techniques along with electron microscopy and magnetic measurements. The results indicate that a structural transformation from spinel to rock salt phase occurs above a critical limit for the lithium concentration (xc), which is determined to be between 0.5< xc≤1 for Fe3–δO4. Magnetization measurements confirm the formation of the LiFeO2 phase with its distinct antiferromagnetic behaviour. Upon lithiation, exchange bias measurements reveal a shift in the hysteresis loops with an asymmetry, which can be attributed to the formation of mosaic-like LiFeO2 subdomains and cationic disorder. The combined structural, spectral-imaging and magnetization characterization techniques enabled us to identify the phases and their distribution during in the lithiation process.