Magnetic characterization of Li1+xMn2-xO4Li1+xMn2-xO4 spinel (0⩽x⩽13)

Li1+xMn2-xO4Li1+xMn2-xO4 spinels have been prepared by wet route technique in the whole concentration range 0⩽x⩽13. Structural analysis has been performed by X-ray diffraction and scanning electron microscopy and Raman spectroscopy. The investigation of impurity phases by magnetic experiments complete the sample characterization, allowing for a comparison with samples obtained by other chemical routes. The analysis of the intrinsic magnetic properties show that the magnetic interactions are Mn3+–O–Mn3+Mn3+–O–Mn3+ interactions in a geometrically frustrated lattice, while the Mn4+Mn4+–Mn4+Mn4+ interactions are negligible, with the consequence that the paramagnetic Curie temperature vanishes in the limit x≃13 where only Mn4+Mn4+ ions remain. A consistent description of both the extrinsic and the intrinsic properties including former investigations of electron paramagnetic resonance has been achieved in relation to the electrochemical properties.