Neutron scattering investigation of the spin dynamics in Li[Mn1.94Li0.04]O-3.94 - art. no. 214409

We present inelastic neutron scattering results on Li[Mn1.94Li0.04]O-3.94 f or temperatures T between 4 K and 295 K. We find that this compound is a ch arge-disordered material, in which both Mn3+-Mn3+ and Mn4+-Mn4+ nonlinear c hains are formed once the electrons have become localized. Unlike the case for the parent material LiMn2O4, we find that the Jahn-Teller active Mn3+ i ons in the Li-doped system are in the low-spin state. We observe critical s lowing down of the Mn4+ -Mn4+ spin fluctuations at T similar to 25 K at whi ch point the fluctuations freeze out, while Mn3+-Mn3+ spin fluctuations per sist at least down to 4 K.