An analytical approach to determine the maximum value of the relative magnetic permeability (original) (raw)

A Novel Technique for the Measurement of relative permeability of magnetic materials

American International Journal of Research in Science, Technology, Engineering & Mathematics, 2017

The permeability of materials is very important in the electromagnetic and field of communication which is growing very fast today. This paper describes the novel techniques for the measurement of relative permeability of the magnetic materials. The two techniques for the measurement of relative permeability are described in detail and the results obtained by both methods are compared. The first measurement technique uses dc excitation to reduce excessive power loss and avoid damage of insulation of the windings. The second method required current clamp meter along with dc excitation for the measurement of relative permeability of the magnetic core. The both methods require less power and easy to determine relative permeability as compared to the other available methods based on ac excitation.

A Note on the Effective Magnetic Permeability of Polycrystals

IEEE Transactions on Magnetics, 2000

Many classical estimates for the effective behavior of heterogeneous materials can be reinterpreted in terms of inclusion problems. However, in the case of cubic polycrystals, a cubic permeability tensor for single crystals has to be written. In the framework of linear behavior, the description of the cubic symmetry reduces to isotropy. The heterogeneity of polycrystals, which results from single crystal anisotropy, cannot be described, and the classical estimates for the overall behavior of heterogeneous materials cannot be used. In this paper, we propose a particular description of the cubic symmetry for the magnetic permeability. We then derive estimates for the effective permeability of polycrystals from the solution of the basic inclusion problem, for both macroscopically isotropic and anisotropic polycrystals.

The effect of complex permeability and agglomeration on composite magnetic systems: A three-dimensional numerical analysis and comparison with analytical models

Journal of Applied Physics, 2008

Magnetic permeability of a composite is investigated using three-dimensional numerical models for static and quasistatic case. To analyze the effect of agglomeration and imaginary part of intrinsic permeability on the effective permeability, inclusions with complex permeability and having random distribution or random distribution with agglomeration were used. Significant deviation of analytical effective medium and Maxwell-Garnett models from numerical results for imaginary part of permeability was observed. We obtained that agglomeration increases the real part of the effective permeability for higher volume fractions and higer intrinsic permeabilities. The effect of agglomeration is even more pronounced for the imaginary part of the effective permeability. Our results thus show that agglomeration and complex intrinsic permeability could explain experimentally observed effective permeability.

Relative Permeability in a 3D Analytical Surface Charge Model of Permanent Magnets

The analytical surface charge model is used to calculate the magnetic field of magnets in 3D in an unbounded domain. The method combines high accuracy with a short calculation time. However, in the classical method the relative permeability of the magnet is assumed to be equal to air. This introduces an error in the resulting magnetic field strength. In this paper the permeability of the magnet is taken into account in the form of a redistribution of magnetic surface charge. As such, an exact solution for the magnetic field at low relative permeability is obtained. The interaction force between two magnets is calculated using the newly obtained expressions for the magnetic field and compared with FEM and measurements.

Dynamic permeability in soft magnetic composite materials

Journal of Applied Physics, 2001

This article reports on an isotropic model of the magnetic susceptibility based on an average field theory and proposes to predict the dynamic behaviors of powder magnetic materials. It was essentially built around a so-called effective demagnetizing factor capable of taking the particle shapes into account. So, for a population of randomly distributed particles of anisotropic shapes like, for instance, needles or flakes, we show that the effective demagnetizing factor of this population of particles can be significantly lowered with regard to the well known value of 1/3 classically used to represent the isotropy state. This phenomenon is interpreted as the natural tendency of particles to form clusters to which a moving demagnetizing factor must be assigned. Taking then the aggregation process of particles into account, the ability of the model to predict the dynamic properties of many composite magnetic materials is successfully demonstrated. Our development is illustrated by experimental results concerning a nickel-zinc ferrimagnetic (Ni 0.7 Zn 0.3 Fe 2 O 4) powder.

A new swept-frequency permeameter for measuring the complex permeability of thin magnetic films

IEEE Transactions on Magnetics, 1988

A permeameter is described which measures the complex permeability of anisotropic thin magnetic films over a continuous fre quency spectrum. The system resolves the permeability into both real and imaginary parts, or magnitude and phase. The frequency span of the permeameter, 0.1-200 MHz, is larger than that of previously re ported permeameters. The system has a measurement error of approx imately one-percent which for the samples used here corresponds to a low level permeance detection limit of about 1 I'm, an order of mag nitude below the previously reported low level limit of 13 I'm. The sys tem is both compact in size and convenient to use, with measurements taken over the whole frequency range in less than a minute. The per meameter combines hoth a new design and construction technique of the permeance measuring jig, with a new application of test equip ment. The permeance measuring jig has a coaxial structure and is built using layers of appropriately milled copper-clad microstrip. A scatter ing parameter test set, driven and controlled by a network analyzer, is used to measure the scattering parameters of the permeance mea suring jig, from which the permeance of a sample may be determined. 1979. He is also a member of the Materials Science & Engineering Faculty at Texas. His current research interests are in the ion beam processing of materials, high dose implant ation , solid phase epitaxy in semiconductors, and amorphous magnetic thin films.

Design and Evaluation of a Measurement Procedure to obtain the Electric Permittivity and the Magnetic Permeability

Elektron

Este artículo presenta una implementación del método de línea de transmisión/reflexión para determinar las propiedades electromagnéticas intrínsecas de materiales desconocidos con permeabilidad magnética relativa distinto de uno. Con un analizador vectorial de redes (AVR), los coeficientes de dispersion de la energía transmitida y reflejada se miden simultáneamente para extraer la permitividad eléctrica relativa y la permeabilidad magnética relativa. La tecnica de extracción clásica de Nicolson-Ross-Weir en el dominio de la frecuencia es explicada extensamente y presentada tal que las ecuaciones pueden ser fácilmente implementadas mediante el Software libre GNU OCTAVE. El desfasaje en los planos de referencia y las mediciones de calibración del conector, son realizadas por un AVR de bajo costo sin la funcion de incorporación. Una línea de transmisión coaxil con conectores N hembra es usada por su bajo costo, con el porta muestras de fácil construcción. El procedimiento de medición e...

A Parallel Derivation to the Maxwell-Garnett Formula for the Magnetic Permeability of Mixed Materials

World Journal of Condensed Matter Physics, 2011

Although mixing formulas for the effective-medium type of approximations for the dielectric permittivities in the infinite wavelength (i.e., quasistatic) limit, such as the Maxwell Garnett formula, have been popularly applied in the whole spectral range of electromagnetic fields, their magnetic counterpart has seldom been addressed up to this day. An effort is thus devoted to the derivation of such an equation to predict the final permeability as the result of mixing together several materials. In a similar fashion to the approach leading to the Maxwell Garnett formula, a model is adopted wherein an originally isotropic host material is embedded with a cluster of spherical homogeneous magnetic particles. It is expected that such obtained formula should find wide applications, and particularly in the light frequency domain in this blossomful era of nanometer technology.

Measurements of Magnetic Permeability of Soft Steel at High Frequencies

2012

The Fermilab Booster does not have a vacuum chamber, which would screen the beam from laminations of its dipoles cores. Therefore the Booster impedance is mainly driven by the impedance of these dipoles. Recently an analytical model of the laminated dipole impedances was developed. However, to match the impedance measurements with calculations one needs an accurate measurement of soft steel magnetic permeability. This paper presents the measurements of high frequency magnetic permeability for soft steel similar to the steel of Booster laminations. The measurements were performed in a frequency range from ~10 MHz to 1 GHz and were based on a study of electromagnetic wave propagation in 30 cm long transmission line built with help of steel strip. Measurements were performed in a DC magnetic field to observe the effect of steel saturation on the high frequency permeability. Both real and imaginary parts of the permeability were measured. As expected their values were decreasing with frequency increase from 10 MHz to 1 GHz and with saturation of steel DC permeability.