The structural and magnetic properties of ${\mathrm{Fe}}_x{\mathrm{Mn}}_{1-x}$ alloy thin films deposited on Cu(001) and on Co/Cu(001) are investigated. A layer-by-layer growth mode of the alloy films in a large range of concentration is deduced from the presence of regular oscillations in medium-energy electron-diffraction intensity. Low-energy electron-diffraction experiments reveal that ${\mathrm{Fe}}_{50}{\mathrm{Mn}}_{50}$ films keep the fcc structure when growing on Cu(001) and on Co/Cu(001). Magneto-optic Kerr effect is used to study the magnetic properties of Co/FeMn bilayers. A temperature-dependent increase in the coercive field of the Co film, when the thickness of the adjacent FeMn film exceeds a certain value, is related to the antiferromagnetic state of the ${\mathrm{Fe}}_x{\mathrm{Mn}}_{1-x}$ alloy.

• Received 19 February 2002

DOI:https://doi.org/10.1103/PhysRevB.66.064419