Synthesis, structure and magnetic properties of nanodimensional La1-xBaxFe0.5Mn0.5O3 perovskites

Here we report synthesis, structure and magnetic properties of low temperature synthesized nanodimensional La1-xBaxFe0.5Mn0.5O3 (x = 0.25, 0.33 and 0.50) perovskites. All the samples crystallize in cubic Pm-3m space group. The additional reflection spots (110) in electron diffraction (ED) requiring doubling of cubic cell parameter suggests the possible ordering of Fe and Mn in B-site. The magnetic property of the nanostructured samples is associated with the ferromagnetic clusters developed at the surface of nanoparticles. Such clusters disappeared subsequent to high temperature annealing. Importantly, unlike the homologous series La0.5Ca0.5Fe0.5Mn0.5O3 and La0.5Sr0.5Fe0.5Mn0.5O3 or electronically equivalent ferromagnetic LaFe0.5Cr0.5O3 (TC ∼ 120 K), La0.5Ba0.5Fe0.5Mn0.5O3 fails to exhibit any long range ordering. This curious observation can be better rationalized by considering the cationic size disorder parameter (σ2 = Σxiri 2 -andlt;rAandgt;2) in A-site rather than the random distribution of Fe and Mn in B-site. © 2018 Elsevier B.V.