  The structure, electronic, and magnetic properties of the Mo-doped perovskite
La0.7Ca0.3Mn1-xMoxO3 (x < 0.1) have been studied. A significant increase in
resistivity and lattice parameters were observed with Mo doping. A marginal
decrease in the Curie temperature Tc and the associated metal-insulator
transition Tp were observed. Magnetization data reveal that long-range
ferromagnetic ordering persists in all samples studied and the saturation
moment decreases linearly as x increases. Enhancement in magnetoresistance at
near Tc in the Mo-doped compounds with an optimum doping value x = 0.05 was
observed. The overall experimental results can be explained by considering the
induced Mn2+ ions with Mo6+ in the Mo-doped systems, with the strong FM
coupling between Mn4+/2+- O - Mn3+.
