High saturation magnetization material in FeCo-based system is widely used in recording media and communication devices. With additional dopant, the magnetic property and structure can be significantly improved. Fe70Co30 films with various N-2 doping were prepared by DC magnetron sputtering in this study. To obtain magnetic properties, which are adjustable by coating parameter, composition control is critical in the fabrication process. The composition of Fe, Co and N was evaluated with an electron probe microanalyzer (EPMA) and the structure analyzed by X-ray diffraction (XRD) for the films with respect to different N-2/Ar ratio. The magnetic properties of saturation magnetization (Ms), coercivity (H-C) and resistivity (rho) were also measured, exhibiting M-S = 15 - 24.5 kG, H-C < 70 Oe and rho = 22 - 156 mu Omega cm. (c) 2004 Elsevier B.V. All rights reserved.