Magnetic anisotropy, phase transitions, and domain structures in films with out-of-plane magnetization

Abstract A phenomenological theory of induced magnetic anisotropy in nanostructures is developed. It is shown that, in magnetic films with out-of-plane magnetization, a complex redistribution of the anisotropy energy-density within the layer volume causes nonlinear and nonmonotonic dependencies of the effective anisotropy on layer thickness. These distributions also account for the continuous character of the transition into the phase with perpendicular magnetization. In the thickness range above this transition, a phase with twisted magnetization favoring multidomain structures appears. Experimental data on Ni/Cu(0 0 1) layered systems are analyzed in terms of this theory.