ELECTRICAL AND MAGNETIC PHASES OF THE LAYERED PEROVSKITE CA4-XLAXMN3O10

We analyze magnetic susceptibility, resistivity and neutron diffractio n measurements of the electron doped triple layered perovskite, or Rud dlesden-Popper class of manganates Ca4-xLaxMn3O10. Near the undoped re gion a paramagnetic insulator to antiferromagnetic insulator transitio n is observed with decreasing temperature and a concomitant change in the conduction process from thermal activation to Mott-type hopping. F or larger doping, with a Mn valence of 3.97, there is a transition fro m the paramagnetic insulator to a canted antiferromagnetic insulator w hich exhibits a more dramatic change in the conduction mechanism. (C) 1998 American Institute of Physics.