The effect of Fe substitution by Al in Sr-2(Fe1-xAlx)MoO6 (0 less than or e
qual to x less than or equal to 0.3) double perovskites is reported. X-ray
diffraction, magnetic measurements and Mossbauer spectroscopy have been use
d in the investigation. Contrary to other substitutions in similar compound
s, Al increases the cationic order up to x = 0.1 and beyond. This ordering
effect is accompanied by an increase in the magnetic moment per Fe atom, bu
t not by corresponding higher Curie temperatures.