Electromagnetic and microwave properties of NiFe/NiFeO multilayer thin films

In this work, [NiFe/NiFeO](10) multilayer thin films were fabricated by magnetron sputtering. The microwave and electromagnetic properties were investigated for different thicknesses, t, of the NiFeO layer (t = 0-6 nm) while the thickness of the NiFe was maintained at 8 nm in every cycle. A clear in-plane uniaxial anisotropy field was induced by an external magnetic field. The in-plane uniaxial anisotropy can be adjusted by tailoring the thickness of the NiFeO layer. When t = 0 nm, the NiFe monolayer, which has a thickness of 80 nm, showed low resistivity (rho) and ferromagnetic resonance frequency (f(r)). By increasing the t from 0 to 6 nm, the rho of the [NiFe/NiFeO](10) films exhibited a significant monotonic increase (from 111.2 to 268.8 mu Omega cm), the f(r) rose from 1.07 to 2.85 GHz, and the saturation magnetization (4 pi M-s) was decreased from 12.7 to 10.8 kG. The real part (mu') of the complex permeability is larger than 100 in the range 0.2-1.9 GHz and the damping coefficient (alpha(eff)) increases to 0.078 for t = 6 nm.