Raman spectroscopic studies of lithium manganates with spinel structure

Raman scattering spectra of a set of lithium manganospinels Li1-x+zMn2-zO4 with 0 less than or equal to x less than or equal to 1 and 0 less than or equal to z less than or equal to 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 [B-2]O-4 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.