Effect of Ni doping in rare-earth manganite La0.7Pb0.3Mn1−xNixO3 (x=0.0-0.5)

With Ni doping, La0.7Pb0.3Mn1−xNixO3 (x=0-0.5) system exhibits decrease of conductivity and increase of metal-insulator transition temperature. This is considered to occur because of the decrease of effective double exchange (DE) interaction due to Ni doping. The presence of majority of Ni2+ states as indicated by the XPS study, govern the transport and magnetic properties of this system. The spin-wave stiffness constant D, characterising the magnon in the low-temperature (TTp) semiconducting phase showing increase of activation energy as conductivity decreases.