Magnetic properties of Fe/Co, Fe/CoFe, and (Fe/Co)/SiO2 multilayer films

Abstract

This paper reports on the systematical investigation into the magnetic properties of Fe/Co, Fe/CoFe, and (Fe/Co)/SiO2 multilayer films. Magnetostriction in Fe/Co and Fe/CoFe films can be controlled by changing the thicknesses of the layers. The Fe/Co film (10/0.5 nm) shows saturation magnetization of more than 2 T and hard-axis coercivity of 1.5 Oe for magnetostriction near zero. The hard-axis coercivity is decreased to 0.8 Oe by 300-°C annealing. A magnetic domain structure suitable for a thin-film head is also established for this film. Additionally, a hard-axis coercivity of less than 1 Oe, a relative permeability of 2000, and a saturation magnetization of approximately 2 T are achieved in (Fe/Co)/SiO2 film [(15/0.5)/5 nm] with no annealing. A controlled domain structure consisting of extended 180° walls is observed in this film.