Ion Bean Deposition of Multilayer Magnetic Films

Abstract

ABSTRACTThis work investigates the modification of Fe based ion beam sputtered magnetic multilayer films in order to realize good soft-magnetic properties. Fe is used as the main magnetic material because it is the single element with the highest saturation magnetization. Then, I attempt to obtain Fe with zero magnetostriction and soft-magnetic properties artificially using a multilayering technique, while maintaining the highest possible saturation magnetization. Magnetostriction is changed by one of two following causes: by a change in the balance between positive and negative magnetostriction layers, as seen in for example Fe/Co film, or by a change in crystal orientation, as seen in for example Fe/Si02 film. Multilayer film with positive and negative magnetostriction layers is confirmed to show the same inverse magnetostrictive effect as that in uniform film. Also, the small crystal grains and the magnetostatic coupling cause a decrease in anisotropy dispersion, and lead to soft-magnetic properties, in the multilayer films. Additionally, the minimum coercivity in Fe/ SiO2 film corresponds well to the maximum in-plane uniaxial anisotropy and the minimum perpendicular anisotropy where magnetization is restricted almost completely in the plane.