Ferromagnetic Resonance Study on Si/NiO/NiFe Films

Abstract

Motivated by the wide application of the antiferromagnetic/ferromagnetic (FM) bilayer structures in high-frequency microwave magnetic devices, the Si/NiO/Ni81Fe19 films with different orientations of NiO buffer layer are deposited by magnetron sputtering technology. The phase, microstructure, hysteresis loop, and angular dependence of FM resonance (FMR) linewidth are investigated by X-ray diffractometer, field-emission scanning electron microscope, atomic force microscope, vibrating sample magnetometer, and electron spin resonance spectrometer, respectively. The Si/NiO(220) film has much smaller grain size than that of Si/NiO(200) film, which is beneficial to grow a high quality NiFe film on Si/NiO(220)/NiFe bilayer structures. The hysteresis loop of Si/NiO(220)/NiFe films shows an obvious exchange bias and a relatively smaller coercivity. The FMR linewidth ( $\Delta {H}$ ) of Si/NiO(220)/NiFe films is much smaller than that of Si/NiO(200)/NiFe films, which is caused by the different structural properties and morphologies of the NiO buffer layer. The Lande $g$ factors and effective damping parameters $\alpha_{\rm eff}$ are also discussed.