Fe-doping induced Griffiths-like phase in La_0.7Ba_0.3CoO₃

The effect of Fe-doping on the magnetic properties of the ABO₃-type perovskite cobaltites La_0.7Ba_0.3Co_1-yFe_yO₃ (0 ≤ y ≤ 0.80) is reported. With no apparent structural change in any doped sample, the Curie temperature (T_C) and the magnetization (M) are greatly suppressed for y ≤ 0.30 samples, while a distinct increase in T_C for the y = 0.40 sample is observed. With the further increase of Fe concentration, T_C increases monotonically. Griffiths-like phases in 0.40 ≤ y ≤ 0.60 samples are confirmed. The formation of the Griffiths-like phase is ascribed to B-site disordering induced isolation of ferromagnetic (FM) clusters above T_C.