Effective Biaxial Anisotropy in Double-Layered Thin Magnetic Films

Abstract

Quantitative experimental results have been obtained in support of a previously developed theory which represents the deformation of the critical curves of multilayered magnetic thin films in terms of effective multiaxial anisotropies. The effective biaxial anisotropy field has been experimentally observed to be proportional to the square of film thickness in the case of thinner films, as expected from the theory. From this dependence, the value of the exchange constant of Ni‐Fe‐Co (70–19–11 wt%) alloy is found to be A=1.6 ×10⁻⁶ erg/cm, which is in fair agreement with the value A=0.86×10⁻⁶ erg/cm obtained from a spin‐wave resonance measurement. Deviation from the quadratic dependence in thicker films has been observed and explained.