Structure And Magnetic Properties Of Sm_xFe_1-x Films And (Fe)x(Sm₂O₃)_1-x Nano-granular Films

With the progress of science and technology, the integration and miniaturization of electro-magnetic devices, the soft magnetic films material used in high-frequency fields attracted more and more attention. The demands for this films include high resistivity p, high saturation magnetization Ms, high permeabilityμand appropriate anisotropy field Hk so as to effectively suppress eddy current loss and to possess high ferromagnetic resonance (FMR) frequency fr (f,∝(Ms,Hk)^1/2), which determines the cut-off frequency for high frequency application. The rare earth-3d transitionmetal intermetallic compounds have higher saturation magnetization Ms, bigger magnetocrystalline anisotropy and magnetostriction, can used in high-frequency fields. Magnetic metal and nonmagnetic insulator matrix, is one of the most interesting films because this kind of films takes the advantages of metal (high Ms,μ)and insulator(p).In this paper, a series of magnetic films SmχFe1-χand magnetic nanogranular films (Fe)χ(Sm2O3)1-χwere fabricated by magnetron sputtering. The structures of the samples were characterized by X-ray Diffraction (XRD) and high resolution transmission electron microscope (HRTEM) while the magnetic properties were systematically studied through vibrating sample magnetometer (VSM). Meanwhile, the high-frequency characteristics of complex permeability and the domain structure of the samples were obtained by using the shorted microstrip transmission-line perturbation method and Magnetic Force Microscope (MFM). The main contents are briefly introduced as follows:1. SmχFe1-χmagnetic films were successfully fabricated by magnetron sputtering. The results show that SmχFe1-χfilms consist of bbc Fe phase and rhomb-centered Sm2Fe17 phase.2. The increasing sputtering power leads to an decrease of Sm content and good magnetic properties of SmχFe1-χfilms. In the range of experiment sputtering power, SmχFe1-χsamples prepared by 120 W, have the best soft magnetic properties.3. With the increase of Sm content of SmχFe1-χfilms, the saturation magnetization 4pMs of the films decrease. SmχFe1-χfilms with different Sm content have different stress. The anisotropy of the SmχFe1-χfilms is mainly caused by the stress, which originates from lattice constant change of Sn2Fe17 phase. The sample with Sm content of 26.2% has maximum anisotropy field, Hk= 550 Oe.4. With the increase of thickness of Sm26.2Fe73.8 films, the crystallization degree of Sm2Fe17 phase and the size of Sm2Fe17 grain were different, the stress of Sm26.2Fe73.8 films were different. The coercivity (Hce and Hch) and anisotropy field Hk of Sm26.2Fe73.8 films change with stress.5. (Fe)x(Sm2O3)1-χnanogranular films were successfully fabricated by magnetron sputtering. The films consist of metal Fe granules are embedded uniformly in Sm2O3 granules matrix.6. The (Fe)0.73(Sm203)0.27 nano-granular films exist a critical thickness of tc= 65±15 nm. Below tc, the films show an in-plane uniaxial anisotropy. For the sample with thickness t=46 nm, Hce=25.3 Oe, Hch=8.6 Oe, Hk=75 Oe, p=143μΩ·m,μ'is more than 140 below 1.5 GHz, ferromagnetic resonance frequency fr is 2.6 GHz.7. The films with thickness above the tc show a perpendicular anisotropy, higher Hc and stripe domain structure, and the increasing film thickness leads to a decrease of MR/MS, an increase of the stripe period, fr>3 GHz and an monotonously increase of the permeability (imaginary part).With sgudying of structure, magnetic properties, anisotropy and high-frequency properties of the samples, the rerults show that SmχFe1-χfilms and (Fe)x(Sm2O3)1-χnanogranular films have good potential application.