the film is composed of an alternate lamination of unit iron layers and unit layers of ferromagnetic iron compound such as fe 3 al , fe 3 si , fe 3 ge and fe 3 ga . the thickness of the both unit layers is less than 70 å . the film has a high saturation magnetization more than 230 emu / g and a high thermal stability so that the film is particularly applicable to a magnetic head core .