Electronic and magnetic properties of LaNi1−xCoxO3, LaCo1−xFexO3 and LaNi1−xFexO3

LaNi1−x Co x O3 shows itinerant d-electron behavior similar to LaNiO3 up to x = 0.5. In the range 0.5 < x < 1.0, the cobalt spin state equilibrium is markedly affected; the localized-itinerant electron transition of LaCoO3 is not seen when x < 0.95. In LaCo1−x Fe x O3, itinerancy of d-electrons decreases with increase in x and the compositions with x > 0.5 are similar to LaFeO3. If x > 0.1, the localized-itinerant electron transition is not seen and the cobalt spin state equilibrium is considerably altered. In LaNi1−x Fe x O3, itinerancy decreases with increase in x. These observations can be satisfactorily explained in terms of Goodenough's energy band schemes.