  Ca2-xLaxFeMoO6 double perovskite with La concentration x = 0 to 0.6 was
synthesized using solid state sintering route. The standard techniques of XRD,
SEM and EDX were applied to characterize the material. Crystal structure of the
samples was stabilized in monoclinic phase with space group P2I/n and lattice
expansion was indicated with the increase of x. The increase of La
concentration gradually suppressed the coexisting minor secondary phase in the
material and simultaneously, EDX results indicated the accommodation of more Mo
atoms in the crystal structure. A significant modification in the surface
morphology of the material was noted from adhesive type surface for x = 0 to
brittle type surface with more grain boundary contributions for La doped
samples. We understand a significant change in magnetic properties (appearance
of cluster glass component, reduction of magnetic moment and indication of
higher TC) and in electrical properties (reduction of metallic character) in
terms of enhanced internal disorder in the material, introduced due to La
doping in double perovskite structure.
