The effect of thermal treatment, composition and substrate on the texture and magnetic properties of FeCo thin films

Magnetostrictive FeCo films (thickness 300 nm) have been produced by RF mag netron sputter deposition. The effects of the substrate, composition and th ermal treatment on the structural and magnetic properties of the films have been determined. Structural analysis was performed using transmission elec tron microscopy and x-ray diffraction. The magnetic properties, including m agnetostriction, were determined by the magneto-optical Kerr effect, magnet ic force microscopy and strain-modulated ferromagnetic resonance. It is fou nd that the magnetic softness of the films is critically dependent on the t exture and strain state of the film. With suitable choices of substrate, co mposition and thermal treatment, these parameters can be controlled, produc ing magnetically soft films while maintaining a high magnetostriction The d ifferential response of the magnetic anisotropy to strain in these films is comparable to the best values achieved by more involved manufacturing proc esses, such as multilayering, showing excellent potential for their use in magnetic sensors and actuators.