Electron paramagnetic resonance of cerium and alkali-doped manganites: a tool for fast characterization within a combinatorial chemistry approach

Cerium. sodium and potassium ions have been substituted to lanthanum and st rontium within the series La(1-x)A(x)MnO(3), starting from the composition La0.8Sr0.2MnO3. The temperature of transition from the high-temperature par amagnetic 'insulating' phase to the low-temperature ferromagnetic conductin g phase has been studied versus composition by electron paramagnetic resona nce. It is shown that. in addition to the resonant line near g equal to 2, characteristic of the paramagnetic phase, a lower-field asymmetric signal a ppears upon cooling in the ferromagnetic phase. The onset of this low-field additional signal scales with that of magnetization, is ascribed, therefor e, to ferromagnetic resonances. (C) 2000 Elsevier Science S.A. All rights r eserved.