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

Stripe structures in ferromagnetic thin films with perpendicular anisotropy and quality factor Q < 1 are numerically investigated using energy minimization. This formulation is applied to films with NiFe-type material parameters, high anisotropy (O(100) Oe) and thickness in the range of approximately 1000 - 2500 angstrom. For a given thickness, these films undergo a transition from a uniform in-plane state to a stripe state characterized by periodic out-of-plane tilt of magnetization as the anisotropy is increased above a critical value. The critical anisotropy decreases with increasing thickness; this critical relationship is calculated and is found to agree well with previous analytic results. The ratio of the stripe-state wavelength to film thickness is 2 on the critical locus but decreases as either the anisotropy or the film thickness is increased. The stray field outside the film surface has an amplitude O(10) Oe and submicron period.