Highly aligned films of composition Sr1.9A0.1FeMoO6 (A=Ca,Ba,La) and undoped control samples, were fabricated on (100) single-crystal LaAlO3 by ultrasonic spray pyrolysis. Compared to undoped films, the doped films showed reduced saturation magnetization and magnetoresistance and the lanthanum-doped film showed a significant increase (∼40 K) in the Curie temperature. The electrical resistivity was well described by a spin-dependent transport model for all the films. The transport spin polarization has been determined with this model, and independently by point contact Andreev reflection spectroscopy. The doped films do not have improved polarization over the undoped films and the maximum P obtained is of the order of 63%. © 2003 American Institute of Physics.