• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.385-390
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• 2008

For taking account of the two-dimensional magnetic properties of a grain-oriented electrical steel sheet, the effective anisotropic tensor reluctivity is examined, and a computationally efficient algorithm is suggested by using the response surface method to model the two-dimensional magnetic properties. It is shown that the reconstructed two-dimensional magnetic properties are fairly effective to stabilize the convergence characteristics of the Newton-Raphson iteration in the nonlinear magnetic field analysis.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.231-235
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• 1990

Soft magnetic silicon steels containing up to 6.5wt% of silicon were prepared by powder metallurgical processing and their magnetic properties were evaluated. The magnetic properties of P/M silicon steels are similarly affected by the silicon addition as those of conventional ingot processed ones but are also significantly affected by density and interstitial impurities particularly oxygen content. Magnetic flux density, $B_{10}$ and coercivity, Hc, tends to decrease with silicon content whereas maximum permeability, ${\mu}m$, decreases first and then increases rapidly above 5 wt% silicon. Increasing density also increases magnetic flux density and maximum permeability but reduces coereivity. The latter two properties are, however, affected more strongly with oxygen content.

• Elastomers and Composites
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• v.51 no.1
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• pp.38-42
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• 2016

For improving the heat loss of a refrigerator around door gasket, it is very important to reduce the amount of rubber magnet used, of which thermal conductivity is much higher than the plastics, and enhancing the magnetic properties of rubber magnet itself is crucial for this. In the present study, therefore, a relationship between the optimum conditions of rubber magnet fabrication process and raw material compositions in the ferrite powder/CPE binder compounds was investigated for finding a way to enhance the magnetic properties of rubber magnet. Magnetic attraction forces of a sample rubber magnet was measured as function of distance, and thermal properties of the sample ferrite powder/CPE binder compound were analyzed with TG/DTA thermal analyzer. As a results, a rubber magnet strip with enhanced magnetic properties was expected to be fabricated, of which raw material compound was prepared by compounding with higher ferrite magnetic powder concentration.

• Journal of the Korean institute of surface engineering
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• v.51 no.4
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• pp.202-206
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• 2018

Permalloy($Ni_{80}-Fe_{20}$) which is known for its soft magnetic properties is a well-known material that has been studied intensively. Permalloy nanoflakes were fabricated with the combination of electrodeposition and sonication process. Ultrasonic power was applied to the deposited alloy which produced nanoflakes in forms of sheet. High internal stress created cracks which helped the peeling of permalloy into nanosheets. Because of shape anisotropy, flakes could be aligned by magnetic field. The magnetic properties of the nanosheets were observed, and the variation of magnetic properties with the alignment of flake was also investigated.

• Journal of Magnetics
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• v.18 no.4
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• pp.405-411
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• 2013

The structural, magnetic and magnetocaloric properties of $CoMn_{1-x}Cr_xGe$ (x=0.05-0.125) have been investigated by using electron microscopy, x-ray diffraction, calorimetric and magnetic measurements. In this study, our aim is to justify the magnetocaloric effect by tuning the structural and magnetic transition temperature with Cr doping on CoMnGe pure system. The substitution of Cr for Mn leads to a decrease of both structural and magnetic transition temperatures. However, structural and magnetic transition temperatures do not close to each other. From magnetization measurement, we calculate that isothermal entropy change associated with magnetic transition can be as high as 3.82 J $kg^{-1}K^{-1}$ at 302 K in a field of 7 T. Meanwhile, structural phase transition contribution to isothermal entropy change is calculated as 5.85 J $kg^{-1}K^{-1}$ at 322 K for 7 T.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.333-338
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• 1999

Thin film inductors of $10 mm \times 10 mm$ with inner coil type of 14 turns were fabricated by sputtering, photo-masking, and etching processes. Their characteristics of impedances and annealing after were investigated. The properties of impedances of the thin film magnetic core inductors with inner coil type were improved by magnetic field annealing due to the removal of residual stress and the improvement magnetic properties of magnetic films. But the characteristics of frequency of the thin film magnetic core inductors were not improved by magnetic field annealing due to properties of the spiral pattern and inner coil type. The thin film magnetic core inductor annealed by uniaxal field annealing method showed an inductance of 1000 nH and resistance of$ 6 \Omega$ of 1 at 2 MHz.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.824-827
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• 1995

Dielectromagnets are permanent magnets made from resin-bonded hard magnetic powders. Magnetic properties of dielectromagnets depend on kind of used hard magnetic materials as chemical compound, shape, size of grain and applied technology. Comparison of advantages and disadvantages of dielectromagnets made from different kind of magnetic powders induced us to try to prepare dielectromagnets from mixture of hard magnetic powders, not only one of them. The purpose of investigation on this kind of dielectromagnets is to find formula to prepare permanent magnets with properties adequate to different kind of electrical motors requirements. As hard magnetic materials we used powders of ferrite, melt-spun ribbon Nd-Fe-B and Alnico. Papers present results of investigation on technology of this kind of dielectromagnets. It shows also influence of kind of mixture and used technology on magnetic properties of dielectromagnets.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.684-689
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• 1991

Magnetic properties of sintered Fe-Si-P alloys have been investigated as a function of sintering condition and composition. Sintering was carried in the temperature range from 1100ø C to 1400ø C in vacuum. As the sintering temperature increases, the magnetic properties of specimens were improved mainly due to the easy movement of domain wall because large pores and large grains were formed during the sintering process at high temperature. When sintered at 1400ø C, Fe-2w/o Si-0.5w/o P compact had the best mgnetic properties, but more phosphorus addition degraded magnetic properties. It appears that the degradation was caused by the formation of non-magnetic compounds such as Si P, Fe3P in the compacts with high phosphorus contents.

• Journal of the Korean Vacuum Society
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• v.4 no.S2
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• pp.24-29
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• 1995

The magnetic amd magneto-optical(MO)properties of Co-based multilayered(ML)films are known to vary sensitively according to the manufacturing methods and the film microstructures. Co/Pd and Co/Pt ML films with ultrathin layers of Co were prepared by alternating deposition in an ultrahigh-vacuum physical-vapor-deposition system. The individual layer thicknesses of the samples were estimated making use of the angular positions of x-ray diffraction peaks. The magnetic and MO properties were investigated, and correlated systematically to the structural parameters of the films. A Kerr spectrometer was self-manufactured to measure the MO properties such as Kerr rotation angle, ellipticity and reflectivity. The rms surface roughness was also measured using atomic force microscopy. Some of the samples showed good properties for MO medium, such as large perpendicular magnetic anisotropy and Kerr rotation, and perfect squareness of the magnetic hysteresis loop.

• Journal of Magnetics
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• v.22 no.2
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• pp.344-351
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• 2017

Wireless magnet pumps are used in medical applications and are particularly useful as artificial heart ventricular assist devices (VADs). To investigate wireless operation of magnetic pumps, we fabricated three types of magnetic impellers using bonded magnets by blending magnetic powders of SmFeN, NdFeB, and Sr-ferrite. We investigated the magnetic properties of the fabricated magnetic impellers, which are driven by the application of magnetic coupling with an external driving magnet or external coil system, without a driving motor, shaft, or mechanical bearings. The use of wireless magnetic pumps is therefore not complicated by critical issues of size, heat, and vibration, which are very important issues for blood pumps. The magnetic properties of the impellers, such as their rotational speed, driving torque and hydrodynamic performance, determine their wireless driving ranges. We conducted performance evaluations of the impeller's magnetic wireless manipulation, heat, and vibration. In addition, we carried out an animal test to confirm the suitability of the wireless magnetic pumps for use as biventricular assist devices (BiVADs).