Morphology Induced Magnetic Anisotropy of Thin Films on Nanoscale MgO- and Si-Ripples

Ion beam erosion techniques allow for the creation of well ordered ripple patterns with nanometer periodicity. Moreover, the periodicity can be tuned over a wide range by changing the ion beam energy [1]. The ripple pattern is directly transferred to the surface of films grown on these substrates. This offers the possibility of tailoring the magnetic properties by inducing additional magnetic anisotropy as well as modifying the intrinsic magnetic damping by adding relaxation mechanisms due to the structural modifications.
We study the influence of rippled vs. flat Si substrates for 10 nm thin Fe and Co films, as well as technologically relevant Heusler alloys (Fe3Si and Co2FexMn1-xSi). The magnetic anisotropy as well as damping is measured by frequency and angle-dependent vector network analyzer ferromagnetic resonance. The ripple morphology of the magnetic layers induces a strong uniaxial magnetic anisotropy. The intrinsic magnetic damping is influenced by mosaicity related inhomogeneous broadening and additional two-magnon scattering.
This work was supported by DFG grant no. FA 314/6-1.