Temperature characteristics and magnetization mechanism of Fe1.2Co films

•The competition mechanism between the ferromagnetic phase and the anti-ferromagnetic phase in Fe1.2Co films was revealed by FC and ZFC analysis.•To find the nucleation and growth of reversed nuclei is a major factor to affect coercivity of Fe1.2Co films.•The crystal FeCo thin films with high density and good flatness were obtained by PLD technology.