Tailoring High-Frequency Properties of Permalloy Films by Submicrometer Patterning

We have measured shape-induced high frequency properties of patterned submicrometer permalloy (Py) arrays. We sputtered and patterned Py films on gold (Au) transmission lines, using chromium (Cr) as adhesion layers for Au and Py deposition. Each Py bar in the arrays is 10 mum long and 100 nm thick. The widths of the Py bars in two different arrays are 240 and 550 nm, respectively. Micromagnetic simulations indicate single domain magnetization distribution in these Py structures. The measured ferromagnetic resonance frequencies without bias field are approximately 11.5 and 8 GHz, respectively. We obtained the corresponding susceptibilities. The experimental results agree with theoretical predictions.