NUMERICAL INVESTIGATION OF STRIPE STRUCTURES IN FERROMAGNETIC THIN-FILMS WITH PERPENDICULAR ANISOTROPY

Stripe structures in ferromagnetic thin films with perpendicular aniso tropy and quality factor Q < 1 are numerically investigated using ener gy minimization. This formulation is applied to films with NiFe-type m aterial parameters, high anisotropy (O(100) Oe) and thickness in the r ange of approximately 1000 - 2500 angstrom. For a given thickness, the se films undergo a transition from a uniform in-plane state to a strip e state characterized by periodic out-of-plane tilt of magnetization a s the anisotropy is increased above a critical value. The critical ani sotropy decreases with increasing thickness; this critical relationshi p is calculated and is found to agree well with previous analytic resu lts. The ratio of the stripe-state wavelength to film thickness is 2 o n the critical locus but decreases as either the anisotropy or the fil m thickness is increased. The stray field outside the film surface has an amplitude O(10) Oe and submicron period.