  In this letter we report the stress induced Mn charge-ordering process in the
LiMn2O4 spinel, evidenced by the lattice strain evolutions due to the
Jahn-Teller effects. In-situ neutron diffraction, reveals that the initial
stage of this process at low stress, indicating the eg electron localization at
the preferential Mn sites during the early phase transition, as an underlying
charge ordering mechanism in the charge-frustrated LiMn2O4. The initial stage
of this transition exhibits as a progressive lattice and charge evolution,
without showing a first-order behavior.
