Positron annihilation studies on the La1-xPbxMnO3 system

Positron annihilation lifetime studies have been carried out on the La1-xPb xMnO3-type magnetoresistive compounds for x = 0.05, 0.1, 0.3, 0.5 and 0.7. Both room-temperature resistivity and mean positron lifetime (<(<tau>)over bar>) data show a dip around x = 0.3. The magnetic susceptibility of these samples also shows a peak around the same concentration (x = 0.3) of Pb. Th e minimum value of <(<tau>)over bar> around x = 0.3 suggests localization o f the electrons arising due to strong electron-phonon interaction. (C) 2001 Elsevier Science B.V. All rights reserved.