Magnetoresistive behavior in hole doped La_(1-x)Pb_xMn_(0.8)Ru_(0.2)O_3 (0.2<=x<=0.4) epitaxial thin films

摘要

Epitaxially grown thin films of La_(1-x)Pb_xMn_(0.8)Ru_(0.2)O_3 (0.2<=X<=0.4) on LAO (001) substrate using pulsed electron deposition technique shows a systematic decrease in metal to insulator transition from 300 to 250 K when hole concentration varies from 40 percent to 20 percent. However, an increase in magnetoresistance ratio by approx 5 percent -15 percent is observed for Ru substituted films at the respective Curie temperatures when compared to the parent La_(0.6)Pb_(0.4)MnO_3 film. Transport and magnetoresistive properties show that Ru substitution maintains a considerable hole carrier density even for La_(0.8)Pb_(0.2)Mn_(0.8)Ru_(0.2)O_3 (8282) composition to stabilize the double exchange interactions.