Magnetic properties of La2MnCo1-xFexO6

The effect of substitution of Fe for Co in the high-Tc phase of ferromagnetic LaMn0.5Co0.5O3, containing Mn3+ and low-spin Co3+ ions, is studied to understand why ferromagnetism is not observed in the related compound LaMn0.5Fe0.5O3. The ferromagnetic transition of LaMn0.5Co0.5O3 is found to be broadened, with a decrease in the magnetization, as Fe is gradually substituted for Co in LaMn0.5Co0.5-xFexO3. The unit cell lattice parameters vary linearly for x>0, following Vegard's law, indicating the possibility of a random distribution of the B-site ions in the perovskite lattice on Fe substitution. The observed magnetic behavior of LaMn0.5Co0.5-xFexO3 (0<x≤0.5) can be best described in terms of random site percolation