Effects Of High Magnetic Field Annealing On Diffusion And Magnetic Properties Of Co/Si(100)

Co films were widely used for high-frequency soft magnetic recording and perpendicular magnetic recording due to their high saturation magnetization and unique crystal structure.It is unavoidable that diffusion between Co films and wafers take place during preparation and using. The diffusion behavior can affect the magnetic properties of Co films severely. Films diffusion has many characteristics, such as films diffusing at lower temperature and higher diffusion speed and a small amount of diffusion having obvious influence on film properties. Due to its unique properties of non-contact, high energy, high magnetic fields as a kind of extreme conditions can have an obvious influence on diffusion. But most of the researchers pay their attention to the diffusion behavior of bulk materials. So the researches on films diffusion under high magnetic field are of great significance.Co/Si(100) diffusion couples were annealed under high magnetic field. The samples were characterized by XRD, XPS, TEM and VSM. We studied the high magnetic field effect on diffusion of Co/Si(100), phase transformation of Co films and magnetic properties. Preliminary theoretical analysis was done using the theory of magnetic free energy and magnetic ordering. Followings are the results:1. With temperature increasing, the effects of high magnetic fields on diffusion between Co and Si are nonlinear, which shows firstly accelerated, then suppressed and then accelerated the diffusion behaviors.2. At lower temperature, high magnetic fields have influence on magnetic properties by accelerating the diffusion between Co and Si. The saturation magnetization and coercivity of Co/Si(100) become smaller under high magnetic fields.3. After high magnetic field annealing at higher temperature, fcc-Co phase exists at room temperature which make the saturation magnetization decrease and coercivity increase. Influence of phase transformation under high magnetic field on magnetic properties are more obvious than those influence of diffusion behavior under high magnetic field.