Raman spectroscopic studies of lithium manganates with spinel structure

Raman scattering spectra of a set of lithium manganospinels Li1−x+zMn2−zO4 with 0 ≤ x≤ 1 and 0 ≤ z≤ 0.33 are reported and analysed. Structural changes have been investigated following the evolution of Raman spectra with the concentration of lithium cations. The local structure was characterized as a function of the mean oxidation state of manganese cations. The trigonal distortion of MnO6 octahedra is evidenced by insertion of lithium ions into the [B2]O4 spinel framework. A comparison with tetragonal Mn3O4 and Fe3O4 spinels shows the influence of the Jahn–Teller effect on the Raman features for this class of materials.