Self-biased microwave ferromagnetic performance of patterned Ni80Fe20 thin films

摘要

Patterned Ni ₈₀Fe₂₀ permalloy films with strip length of 5 mm, strip distance of 40 μ m and various ferromagnetic (FM) strip widths from 20 to 40 μ m were prepared by pulse laser deposition and photolithography for study the microwave performance of permalloy films. Comparing with the continuous magnetically isotropic permalloy film, the anisotropy fields H_K increase with the decrease of the FM strips’ width. As a result, the ferromagnetic resonance frequency f_r is enhanced from 1.71 GHz of continuous film to 2.1 GHz of patterned film with FM strip width of 20 μ m . The comparison between f_r and H_K demonstrates that the enhancement of f_r can be attributed to the increase of H_K due to the shape anisotropy of permalloy strips.