The magnetic domain structures in thin FexNi(1-x) alloy films grown on Cu(111) have been investigated by the photoemission electron microscope (PEEM). By tuning the photon energy to respective x-ray absorption edges, element-specific information can be obtained with PEEM. We have observed clear ferromagnetic domains on samples with an iron concentration of xless than or equal to0.6 and x = 1.0. The PEEM images indicate that Fe and Ni form a good alloy on Cu(111), with the same domain structures and the magnetization in each domain aligned for both elements. The domain sizes and shapes exhibit dependence on thickness, stoichiometry x, and substrate quality. (C) 2004 American Vacuum Society.