Nucleation of weak stripe domains: Determination of exchange and anisotropy thermal variation

The phenomenon of stripe domain nucleation is deeply investigated both theoretically and experimentally in FePd films by the rigorous micromagnetic theory of domain nucleation and x-ray resonant magnetic scattering. The critical domain width and the nucleation field are determined by measuring the magnetic satellite peak position and integrated intensities in a wide temperature interval up to 400 degrees C (0.9T(c)) at varying in-plane magnetic fields for each temperature value. We develop and demonstrate a procedure that allows us to determine directly from the micromagnetic treatment the exchange stiffness constant A and the first order anisotropy constant K-u as a function of temperature. The proposed procedure, based on linearized micromagnetic equations at the critical field, is valid for magnetic films with perpendicular magnetic anisotropy, and is therefore effective to measure A and K-u in a technologically relevant class of materials.