  Here, we report structural and optical properties of (ALa)(FeMn)O6 (A = Ba
and Sr) double perovskite synthesized via auto-combustion followed by a
calcination process. Rietveld refinement of the structure using x-ray
diffraction data reveals that (BaLa)(FeMn)O6 crystallizes into cubic crystal
structure with space group Pm-3m while (SrLa)(FeMn)O6 crystallizes into
rhombohedral crystal structure having space group R-3c. The absorption spectrum
measurement using UV-Vis spectroscopy reveals that these samples are perfect
insulator having an energy band gap between conduction and valence band of the
order of 6 eV.
