Oblique deposition conditions of Si were used to create a periodic compositional defect matrix in Fe${}_3$Si${}_{}$/MgO(001) thin films. The modified growth conditions provoke shadow effects, which lead to a two-magnon scattering channel with twofold symmetry in the film plane. Its axis is controlled by the sample orientation with respect to the Si evaporator. Angular-dependent ferromagnetic resonance data reveal an enhanced magnetic-relaxation rate induced by the dipolar interactions originating from these artificially created defect structures, while magnetic anisotropy is shown to be influenced negligibly. Experimental results agree well with the developed theoretical approach allowing one to distinguish different relaxation channels.

• Received 21 December 2011

DOI:https://doi.org/10.1103/PhysRevB.85.014420