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Magnetic Permeability (magnetic + permeability)

Distribution by Scientific Domains
Engineering66%
Physics and Astronomy33%

Selected Abstracts

Design and application of layered composites with the prescribed magnetic permeability

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 1 2010
Jae Seok Choi
Abstract This research aims to design the microstructure with the prescribed magnetic permeability and proposes a design method to control the magnetic flux flow using layered microstructures. In the optimization problem for the microstructure design, the objective function is set up to minimize the difference between the homogenized magnetic permeability during the design process and the prescribed permeability based on the so-called inverse homogenization method. Based on the microstructure design result, a microstructure composed of layered materials is proposed for the purpose of the efficient magnetic flux control. In addition, its analytical calculation is added to confirm the feasibility of the optimized results. The layered composite of a very thin ferromagnetic material is expected to guide the magnetic flux and the performance of the magnetic system can be improved by turning the microstructures appropriately. Optimal rotation angles of microstructures are determined using the homogenization design method. The proposed design method is applied to an example to confirm its feasibility. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The reduced scalar potential in regions with permeable materials: Reasons for loss of accuracy and cancellation

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 4 2007
S. Balac
Abstract Practical three-dimensional magnetic field problems usually involve regions containing current sources as well as regions with magnetic materials. For computational purposes, the use of the reduced scalar potential (RSP) as unknown has the advantage to transform a problem for a vector field throughout the space into a problem for a scalar function, thus reducing the number of degrees of freedom in the discretization. However, in regions with high magnetic permeability the use of the RSP alone usually results in severe loss in accuracy and it is recommended to use both the RSP and the total scalar potential. Using an asymptotic expansion, we investigate theoretically the underlying reasons for this lack of accuracy in permeable regions when using the RSP as a unique potential. Moreover, this investigation leads to an efficient numerical method to compute the magnetic field in regions with high magnetic permeability. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Magnetic loading of EBG AMC ground planes and ultrathin absorbers for improved bandwidth performance and reduced size

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2006
D. J. Kern
Abstract This paper demonstrates the advantages of magnetic loading within the substrate of an electromagnetic bandgap (EBG) surface. A conventional EBG surface has been shown to act as an artificial magnetic conductor over a narrow bandwidth. This paper demonstrates that by magnetic loading of the substrate, increased operating bandwidth is achieved for each resonant frequency. In addition, previous research has revealed that an ultrathin electromagnetic absorber design can be obtained by introducing loss into the frequency selective surface of an EBG absorber. It is now shown that a further reduction in thickness is possible by including a small amount of magnetic permeability within the dielectric substrate material. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2468,2471, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21972 [source]

Magnetic properties of Fe76X2B22 (X=Cr,Zr,Nb) amorphous alloys

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
A. Chrobak
Abstract The paper contains experimental results referring to optimization of soft magnetic properties and crystallization in the Fe76X2B22 (X=Cr,Zr,Nb) amorphous alloys. We have used measurement of thermomagnetic balance, magnetic permeability, coercive field and also HREM and X-ray diffraction techniques. It was shown that Zr and Nb alloying additions cause a slowing down of diffusion processes and an increase of the annealing for 1 hour optimization temperature of about 50 and 100 K, respectively. Activation enthalpies of the crystallization process were determined as: 2.0 eV (X=Cr), 2.6 eV (X=Zr) and 4.4 eV (X=Nb). [source]

Study of the magnetic disaccommodation in La doped YIG

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2005
C. Torres
Abstract The relaxation of the initial magnetic permeability of La doped yttrium iron garnet (YIG) samples with nominal composition Y3,xLaxFe5O12 (0< x <0.6) is analysed in this work. The results show a very different behaviour depending on the sintering atmosphere used for the fabrication of the samples. Concretely, for the samples sintered in air, it just have been detected the usual relaxation peak found in YIG at 130 K. However, a new relaxation peak appears around room temperature for the samples sintered in CO2 atmosphere when the La content is at least of 0.3. These results have been interpreted in terms of the formation of a secondary perovskite phase when the La solubility limit is reached. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]