Phase separation as origin of the magnetic anomalies in La0.85Sr0.15CoO3

The dependence of the ac-magnetic susceptibility of La0.85Sr0.15CoO3 on the annealing temperature used during synthesis is addressed. Such dependence has been previously attributed to compositional inhomogeneities. Neverthele ss, the presence of distinct phases with different chemical compositions is excluded after explorations by several techniques. Instead it is proposed that an electronic phase separation takes place in the material, whose stat e is changed after charge-carrier redistributions due to the thermal histor y of the samples, analogously to parent manganese-based perovskites. (C) 20 01 American Institute of Physics.