  LaCu3Fe4O12 undergoes a phase transition at 393 K involving the spin order
(SO) of the Fe sites and the charge order (CO) resulting in Cu-Fe intersite
charge transfer. On the basis of density functional calculations, we show that
this simultaneous CO/SO phenomenon is a consequence of two electronic effects,
namely, the competition between the Fe-Fe and Fe-Cu antiferromagnetic spin
exchange and the dependence of the width of the Fe d-block bands on the SO of
the Fe atoms.
