  FeGa3 is a well known d-p hybridization induced intermetallic bandgap
semiconductor. In this work, we present the experimental and theoretical
results on the effect of Al substitution in FeGa3, obtained by x-ray
diffraction (XRD), temperature dependent resistance measurement, room
temperature Mossbauer measurements and density functional theory based
electronic structure calculations. It is observed that upto x = 0.178 in
Fe(AlxGa1-x)3, which is the maximum range studied in this work, Al substitution
reduces the lattice parameters 'a' and 'c' preserving the parent tetragonal
P42/mnm crystal structure of FeGa3. The bandgap of Fe(AlxGa1-x)3 for x = 0.178
is reduced by ~ 24% as compared to FeGa3. Rietveld refinement of the XRD data
shows that the Al atoms replace Ga atoms located at the 8j sites in FeGa3. A
comparison of the trends of the lattice parameters and energy bandgap observed
in the calculations and the experiments also confirms that Al primarily
replaces the Ga atoms in the 8j site.
