Synthesis, microstructure, the complex nature of the magnetic state of lanthanum manganite weakly doped by bismuth

Resumo

Structural, magnetic, and resonance studies of Bi_xLa_1–xMnO₃ are performed. Nanopowders of weakly doped compounds (x = 0.0–0.1) with particle sizes of ≤40 nm are prepared using the sol–gel technique. Nanopowder sintering under the same conditions leads to a sharp increase in the mean granule size with increasing Bi concentration. The 55Mn NMR signal of manganites prepared via solid synthesis corresponds to rapid exchange Mn⁴⁺ ↔ Mn³⁺. Measurements of the magnetic susceptibility reveal an inhomogeneity in the ferromagnetic state of the Bi_xLa_1–xMnO₃ system.