Influence of processing on the Li:Mn ratio in spinel phases of the system Li1 + xMn2 − xO4 − δ

Abstract The composition of the spinel phase in the system LiMnO is studied under the influence of a controlled gas atmosphere and temperature/time schedule. The existence of an extended spinel phase of composition Li[Mn 2 − x Li x ]O 4 − δ (0 ≤ x ≤ 1 3 ) is shown. The Li Mn ratio as well as the proportion between Mn 3+ and Mn 4+ is adjustable by the method of preparation. LiMn 2 O 4 − δ can be prepared in a cubic and tetragonal modification. According to magnetic and spectroscopic measurement, no simple ionic model can describe the electron structure throughout the entire series of solid solution. A partial charge delocalization takes place resulting in a reduction of the total number of unpaired electrons. At lower temperatures a spin glass behaviour develops due to the inherent frustration of the octahedral antiferromagnetic sublattice. The freezing temperature depends on the Li Mn ratio and decreases with increasing x .