Crystallization and magnetic properties in amorphous Co2MnSi alloy films

Amorphous Co2MnSi alloy films with weak ferromagnetic property were fabricated by sputtering at room temperature. A strong ferromagnetic transition is revealed when the film crystallizes into an ordered structure upon annealing at 400 °C. The structural magnetic transition of the film is further confirmed by thermomagnetic measurements. A remarkable decline in the optical reflectance with temperature is observed upon crystallization. The transition is found to be a thermal activated process and the activation barrier is optically determined to be 1.07 eV.