Magnetization Measurements and ⁵⁷Fe Mössbauer Studies of LaNi_1−xFe_xO₃ (0.0≤x≤0.2)

Abstract

Magnetization measurements and ⁵⁷Fe Mössbauer study of LaNi_1−xFe_xO₃ (0≤x≤0.2) were made. Temperature independent susceptibility of LaNiO₃ increases with Fe substitution. At high temperatures, the increment of the susceptibility due to Fe, obeys the Curie-Weiss law, with μ_eff of 4 μ_B/Fe. At low temperatures, a small amount of remanent magnetization appears and the Mössbauer spectra show hyperfine magnetic splittings. The value of H_hf (\simeq400 kOe) extrapolated to 0 K and that of IS (\simeq0.34 mm/s) are considerably smaller than the typical ones for Fe³⁺ in octahedral sites in ionic oxides. The magnetically ordered phase at low temperatures seems to be a spin-glass or a mictomagnet in which Fe³⁺ moments are frozen, coupled by long range exchange interactions in addition to the nearest neighbor superexchange interactions.