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High magnetic field was introduced to improve the saturation magnetostriction of cast Fe81Ga19 alloy during annealing process. The effects of high magnetic field on the microstructure, magnetic domain structure and magnetostrictive properties were investigated in this paper. Results indicated that high magnetic field could transfer Ga atom from precipitation to parent phase. High magnetic field also enhanced [1 0 0] direction orientation of FeGa alloy. The saturation magnetostriction for Fe81Ga19 alloy annealed at 10 T increased by about five times compared to one without high magnetic field. The improvement in saturation magnetostriction is attributed to the enhanced [1 0 0] orientation and Ga diffusion under high magnetic field during annealing process.

This paper focuses on improving the permeability of Fe-Si-B based amorphous magnetic powder cores by addition of micron-sized ferromagnetic crystalline metal particles (Permalloy). The effects of Permalloy content, size and the amount of insulation on magnetic properties and density were investigated. The results showed that the Fe based amorphous powder cores prepared with 15 wt.% Permalloy (

Behavior of spin waves was investigated in patterned Mu-metal thin film both theoretically and experimentally. The Mu-metal(111) thinfilms with 7 nm thickness were grown by thermal evaporation technique in high vacuum condition. X-ray diffraction measurements showed that the film has a highly FCC crystalline structure. Saturation magnetization and coercive field values of sample obtained from vibrating sample magnetometer are around 500 emu/cm3 and 10 Oe respectively at room temperature. The patterns were square shaped and size of squares were changed between 40–80 µm. Theoretical model and computer program were developed for analyzing the FMR spectra. There is no magnetic anisotropy for in-plane and out-of-plane geometry by both theoretical and experimental investigations. Magnetostatic modes were observed for out-of-plane geometry and these modes were highly compatible with outputs of simulation model.

In this work, iron-based soft magnetic composites coated with the amorphous SiO2 layer have been fabricated by utilizing tetraethoxysilane in the reverse microemulsion method, and then the effects of addition amount of SiO2 and annealing temperature on the magnetic properties were investigated. The results show that the surface of iron powders contains a thin amorphous SiO2 insulation layer, which effectively decreases the magnetic loss of synthesized magnets. The magnetic loss of coated samples decreased by 87.8% as compared with that of uncoated samples at 150 kHz. Magnetic measurements show that the sample with 1.25 wt% SiO2 has an acceptable real part and minimum imaginary part of permeability in comparison with other samples. Also, the annealing treatment increased the initial permeability, the maximum permeability and the magnetic induction and decreased the coercivity with increasing temperature in the range 300–600 °C. The results of the loss separation imply that the annealed SMCs have a higher hysteresis loss coefficient (k2) and lower eddy current loss coefficient (k3) as compared with the pure iron compacts after the same heat treatment due to the preservation of the SiO2 layer.

The exchange bias of the soft ferromagnet mu-metal, Ni77Fe14Cu5Mo4, with the metallic antiferromagnet Fe50Mn50 has been studied as a function of ferromagnet thickness and buffer layer material. Mu-metal exhibits classic exchange bias behavior: the exchange bias (HEB) and coercive fields scale inversely with the ferromagnet's thickness, with HEB varying as the cosine of the in-plane applied field angle. While the exchange bias, coercivity, and exchange energy are greatest when the buffer layer material is (111) oriented Cu, amorphous Ta buffers allow the mu-metal to retain more of its soft magnetic character. The ability to preserve soft ferromagnetic behavior in an exchange biased heterostructure may be useful for low field sensing and other device applications., 9 pages, 6 figures

We prepared an Fe-based ribbon with controlled permeability and low magnetic loss by Continuous Stress-Annealing by Joule Heating (CSA-JH) method. The shortest annealing time necessary for the obtaining of the ribbons with completely developed anisotropy was 1 sec, but in order to obtain the sufficiently crystallized ribbons with small saturation magnetostriction it is required to perform annealing longer than 2 sec. A toroidal core was prepared from a long ribbon with controlled permeability and small saturation magnetostriction, and the magnetic loss and relative permeability of the core were evaluated in the frequency range of 0.1 - 3 MHz. The permeability was kept constant up to 2 MHz, and the magnetic loss is lower than that for other types of core with a similar permeability value. These results suggest that the CSA-JH method is a promising method for realizing an Fe-based core with excellent magnetic properties., Proceedings of the 18th International Symposium on Soft Magnetic Materials, Journal of Magnetism and Magnetic Materials, 320(20), pp.e833-e836; 2008

The change of magnetic properties of soft magnetic composites filled with iron cobalt particles from 10 to 80 vol% filler fraction due to an alignment of particles by an external uniaxial magnetic field was measured. Relative changes of permeability values due to an alignment show an increase with a maximum at 30 vol% filler fraction and losses are reduced for frequencies f >50 Hz. Inner demagnetizing fields are reduced evoked by a more micro-homogeneous structure of the composite sample material.

Ferromagnetic powders which are surrounded by an electrically insulating film (soft magnetic composites (SMCs)) exhibit unique magnetic properties, such as relatively low magnetic losses and 3D isotropic magnetic behavior. In some electromagnetic applications, including microwave frequency range applications, it is necessary to increase electrical resistivity without any noticeable reduction in magnetic properties. To achieve this purpose, electrically resistant materials, for example, ferrites with acceptable magnetic properties, are suitable candidates. This paper focuses on the effects of the synthesized Ni–Zn ferrite addition on the magnetic properties of the SMCs containing Ni–Zn ferrite within iron particles. The structure was studied by means of X-ray diffraction (XRD). The microstructure and the powder morphology were examined by the use of scanning electron microscopy (SEM). The magnetic measurements on powders and samples were carried out using a vibrating sample magnetometer (VSM) and an LCR meter, respectively. The results indicate that the lowest magnetic loss and the highest magnetic permeability are related to the composites with 20 wt% ferrite and 2 wt% ferrite, respectively. Also, the composites with 10 wt% ferrite show a good combination of magnetic loss and magnetic permeability in the range 0–500 kHz.

We report complex magnetic permeability or susceptibility measurements of three different laboratory-synthesised magnetic fluids. Microwave frequency range is used for the measurements. We used the reflection/transmission method in a coaxial line cell to obtain the complex permeability μ*. We have subjected the coaxial cell to a constant magnetic field applied parallel to the propagation direction. Nicholson–Ross equations are used to calculate the apparent permeability. Complex magnetic permeability is measured for three different magnetic fluids at microwave frequencies, at different DC-magnetic fields as well as temperatures. It is found that Mn–Zn and Mn–Zn–Gd samples show magnetic resonance behaviour while Mn–Fe sample shows both Neel relaxation and resonance phenomena in the DC applied magnetic field. The effective anisotropy constant and the anisotropy field measured on Mn–Fe fluid are much greater than the effective anisotropy constant and the anisotropy field measured on Mn–Zn and Mn–Zn–Gd fluids.

Fe-Si/Permalloy and Fe-Ni/Permalloy multilayered films were prepared by a conventional rf sputtering method. A Permalloy interlayer is effective in obtaining high initial permeability and a good correlation between the permeability and the (110)/(211) X-ray diffraction intensity ratio was found. This result indicates that the crystal orientation of grains plays an important role in obtaining a high initial permeability. The permeability of the Fe-Si/Permalloy multilayered films decreases after annealing processes above 400°C because of the diffusion of Ni atoms into the Fe-Si alloy layer. To prevent the influence of Ni diffusion and also to improve the thermal stability, the thickness ratio of Fe-Si/Permalloy was found to be important.

Fe-Al-Ti alloy films were prepared at 673 K by an electron-beam evaporation method. Excellent soft magnetic properties (a permeability of about 2000 at 5 MHz and a magnetization of about 1.9 T) were obtained. It is suggested that it is possible to develop soft magnetic film materials with high saturation magnetization, high permeability and small magnetostriction in and Fe-Al alloy system.

This work presents comparative results of magnetic measurements (coercive field, saturation magnetization and anisotropy) performed on thin Ni 81 Fe 19 and Ni 80 Fe 15 Mo 5 films (50–600 nm thick) deposited by rf plasma sputtering at various power values (0.55–3.3 W/cm 2 ), with respect to the deposition parameters and thermal annealing.