CONTROLLED REDUCTION AND OXIDATION OF LA0.85SR0.15MNO3 SINGLE-CRYSTALS

La0.85Sr0.15MnO3 single crystals were grown by the floating zone metho d. They can be reversibly reduced under controlled oxygen partial pres sure. Their defect chemistry is investigated together with the evoluti on of their cell parameters and that of their electric conductivity wh ich is very sensitive to their oxygen content. On the other hand, stoi chiometric crystals can be oxidized with a slow kinetics making possib le the preparation of diphasic materials. (C) 1997 Elsevier Science S. A.