Magnetic Order in Li-Mn Spinels

Magnetic measurements were carried out on different samples of Lithium-Manganese spinel LiMn 20 4 , great care having been taken to avoid the presence of spurious magnetic phases, such as Mn 3 0 4 . Susceptibility data, showing deviations from paramagnetic behaviour at about 40 K, were analyzed in terms of local magnetic interactions, taking into account the structural and transport properties of these compounds. The magnetic response of pure and stoichiometric samples suggests that the onset of a longrange magnetic ordering is hindered by the topological frustration of the antiferromagnetic octahedral sublattice of the spinel.