The use of Co79Cr21 undercoats for controlling the soft magnetic properties of RF sputtered Permalloy thin films

The effects of Co₇₉Cr₂₁ undercoats and nucleating layers on the coercive force, anisotropy field, and 5 MHz to 100 MHz complex permeability spectra of magnetically soft, Ni₈₁ Fe₁₉ thin films RF sputtered onto glass substrates are investigated. While very thin layers of HCP oriented Co₇₉Cr ₂₁≈5 nm, do not affect the coercive force of the NiFe layer, they do increase the measured anisotropy. Thicker CoCr layers increase both the coercive force and anisotropy field. The 5 nm layers of Co₇₉Cr₂₁ act to increase the magnitude of the μ\´ spectra, μ=μ\´-jμ", while decreasing the μ" spectra; thicker layers of CoCr reduce both μ\´ and μ"