ABSTRACT
Pulsed electron deposited thin films of Ru substituted La(1-x)Pb(x)Mn(0.8)Ru(0.2)O(3) (0.2≤x≤0.4) show an increase in the magneto-resistance ratio by â¼5-15% at the respective metal to insulator transition (T(MIT)) temperature when compared to the parent La(0.6)Pb(0.4)MnO(3) thin film. A systematic decrease in T(MIT) is observed from â¼310 to â¼260 K when the hole (Pb) concentration varies from 40 to 20% with constant 20% Ru substitution at the Mn site. The x-ray rocking curve and high-resolution transmission electron microscopy (HRTEM) images of the thin films suggest that Ru occupies the Mn site and shows epitaxial growth of the films on the LaAlO(3) (LAO) substrate. Transport and magneto-resistive properties show that Ru substitution maintains a considerable hole carrier density (due to Mn(4+):t(2g)(3)e(g)(0)/Ru(5+):t(2g)(3)e(g)(0)) even for La(0.8)Pb(0.2)Mn(0.8)Ru(0.2)O(3) (8282) composition, which influences the double exchange interactions.