Phase diagram of low doping manganites

We present a study performed on several LaMnO3+x/2 compositions. Detailed analysis around x = 0.09 detects phase separation between a higher transition, T-c, and a lower one T-N, with coexisting fluctuating and magnetically ordered clusters (the Neel point, T-N, being the onset of an inhomogeneous non-collinear antiferromagnetic order detected by neutrons). The ordered clusters give rise to an extremely fast, static Kubo-Toyabe muon depolarization, while mixed static and dynamic local fields are detected inside the fluctuating clusters. Below T-N precession frequency lines are resolved, despite the huge broadening introduced by localized Mn4+ ordered moments. A phase diagram is obtained and briefly discussed in the context of electronic phase separation. (C) 2000 Elsevier Science B.V. All rights reserved.