Variation of thin film edge magnetic properties with patterning process conditions in Ni80Fe20 stripes

The authors report the effect of etch depth on the magnetic properties of thin film edges in magnetic nanostructures. In transversely magnetized stripes of 20-nm-thick Ni80Fe20, they use ferromagnetic resonance spectroscopy to measure the edge saturation field and effective out-of-plane stiffness field of the trapped-spin-wave edge mode as a function of ion etch depth. With increasing etching depth, the edge surface angle changes from 47° to 80°, and the field required to saturate the edge magnetization perpendicular to the stripe axis nearly doubles. This trend is largely confirmed by micromagnetic modeling of the edge geometry.