Out-of-Plane Magnetic Anisotropy and Microwave Permeability of Magnetoelastic FeCoSiB Amorphous Thin Films

Theamorphous magnetoelastic Fe66Co17Si1B6 thin films have been deposited by dc magnetron sputtering. A lot of ＂nano-trenches＂ have been observed on the fdm surfaces by AFM. The permeability of amorphous Fe66COlTSilB6 thin films was measured within the frequency range of 0.6GHz-10.2 GHz. The ferromagnetic resonance frequency was found to be 1.2 GHz. MFM shows that the domain of thin film is a maze-type pattern, which indicates that an out-of-plane magnetic anisotropy exists. The out-of-plane anisotropy is believed due to the stress-induced magnetic anisotropy. It can be inferred that the internal stress is tensile stress and normal to the film plane. Index Terms

Effect of Sedimentation on the Microwave Permeability of FeSiAl Composites

In order to achieve an easy fabrication and considerable directional orientation, we use a sedimentation method to prepare composites consisting of Fe Si Al flakes. The flakes are dispersed in hydroxylated acrylic resin solution in sonication and natural form into laminated composite samples. Then, the toroidal rings are made with the prepared laminated composite samples. Compared with random orientational Fe Si Al flakes in the composite, the complex permeability of laminated sample has been obviously improved when microwave frequency is below 4 GHz, especially for the imaginary part. A model is proposed to explain the formation reason of aligned Fe Si Al composite by this method. Damping factor（α） is calculated by the combination of the effective medium theory and Landau-Lifshitz-Gilbert equation, and the permeability of the samples is verified by these theories.

Microwave Magnetic Properties of Laminates with Thin FeCoBSi Films

The microwave permeability of laminated composites based on thin FeCoBSi films was under study.The level of permeability increased with increasing of the ferromagnetic inclusions in the laminates.The intrinsic permeability spectra of ferromagnetic inclusion are parametrically reconstructed.The obtained parameters of magnetic resonance were specially analyzed.To avoid the effect of eddy current and to obtain large-volume fractions of ferromagnetic constituent,laminates consisting of alternating FeCoBSi/SiO2 multi-layers and mylar substrates were also investigated.For the same volume fractions of ferromagnetic constituent （8.7%）,laminates based on multi-layered films are found to possess higher values of permeability than those based on one-layered films.

Er^(3+)-substituted W-type barium ferrite: preparation and electromagnetic properties

Er3+-substituted W-type barium ferrites Ba1-xErx(Zn0.3Co0.7)2Fe16O27 (x=0.00, 0.05, 0.10, 0.15, 0.20) were synthesized by polymer adsorbent combustion method. Samples were characterized by X-ray diffraction analysis (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and network analyzer to investigate the relationships among Er3+ concentration, crystal structure, surface morphology and electromagnetic properties. All the XRD patterns showed pure phase of W-type barium ferrite when x≤0.15, while the impurity phase of ErFeO3 appeared when x=0.20. The pure W-type barium ferrite showed a hexagonal flake shape. In addition, the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz. It was indicated that the electromagnetic properties were significantly improved when Er3+ doping content was 0.10. The reasons were also discussed using electromagnetic theory. The optimized ferrite exhibited excellent microwave absorption performance. The maximum of reflection loss (RL) reached about-27.4 dB and RL was below-10 dB at the frequency range from 8.4 GHz to 18 GHz, when the thickness was 2.6 mm.