The bounds of saturation magnetostriction in polycrystalline materials
01 Dec 1997-Journal of Applied Physics (American Institute of Physics)-Vol. 82, Iss: 12, pp 6138-6141
TL;DR: In this article, the authors calculate the alternative approximation of uniform strain in terms of the grains orientation distribution (texture) function, and single crystal constants describing the elastic and magnetostrictive anisotropy.
Abstract: The universally used approximation for the magnetostriction constant of a polycrystalline material is based on the assumption of uniform stress through the aggregate In this article we calculate the alternative approximation of uniform strain The calculation is performed in terms of the grains orientation distribution (texture) function, and single crystal constants describing the elastic and magnetostrictive anisotropy These bounds represent the optimum solution of the incompletely specified problem of crystallites shape distribution in a polycrystalline aggregate The available experimental data are compared with the two approximations
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TL;DR: In this article, the Green's function technique was used to determine the effective magnetostriction of polycrystals with cubic magnetostrictive crystallites and pores, and two extreme approximations of the Reuss and Voigt-type were given.
Abstract: Explicit relations for determining the effective magnetostriction of polycrystals with cubic magnetostrictive crystallites and pores are derived based on the Green’s function technique. For comparison, two extreme approximations-the Reuss and Voigt-type approximations-are also given. To illustrate the technique, the influence of porosity on the effective saturation magnetostriction of common magnetostrictive metals (Fe and Ni), giant magnetostrictive alloy terfenol-D, and Fe–Co spinel are illustrated. The theoretical estimates show an interesting nonmonotonic concentration dependence of magnetostrictive behavior of the polycrystals with such magnetostrictive microcrystallites as Ni and Fe–Co spinel, whose magnetic easy axes are 〈100〉 axes rather than 〈111〉 axes.
12 citations
TL;DR: In this paper, the effective magnetostriction of a two-phase fibrous composite and a polycrystal assembled from cylindrical magnetostrictive cubic crystals is studied.
Abstract: The effective magnetostriction of a two-phase fibrous composite and a two-dimensional polycrystal assembled from cylindrical magnetostrictive cubic crystals is studied. For the considered systems, we show that there exist exact microstructure-independent relations between the effective magnetostriction and the effective elastic moduli. The fibers could be aligned identically or randomly oriented in the transverse plane. There is no restriction on the cross-sectional shapes of the fibers, nor on the arrangement of transverse geometry of the composite aggregate. These connections imply that knowledge of the effective elastic moduli will readily provide the effective magnetostriction of the composite medium.
6 citations
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Book•
01 Jan 1985
TL;DR: In this paper, the physical properties of crystals systematically in tensor notation are presented, presenting tensor properties in terms of their common mathematical basis and the thermodynamic relations between them.
Abstract: First published in 1957, this classic study has been reissued in a paperback version that includes an additional chapter bringing the material up to date. The author formulates the physical properties of crystals systematically in tensor notation, presenting tensor properties in terms of their common mathematical basis and the thermodynamic relations between them. The mathematical groundwork is laid in a discussion of tensors of the first and second ranks. Tensors of higher ranks and matrix methods are then introduced as natural developments of the theory. A similar pattern is followed in discussing thermodynamic and optical aspects.
8,520 citations
Book•
01 Jun 1972
TL;DR: In this paper, the authors present materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
Abstract: Introduction to Magnetic Materials, 2nd Edition covers the basics of magnetic quantities, magnetic devices, and materials used in practice. While retaining much of the original, this revision now covers SQUID and alternating gradient magnetometers, magnetic force microscope, Kerr effect, amorphous alloys, rare-earth magnets, SI Units alongside cgs units, and other up-to-date topics. In addition, the authors have added an entirely new chapter on information materials. The text presents materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
6,573 citations
TL;DR: In this article, the authors established and applied variational theorems for the derivation of bounds for the effective magnetic permeability of macroscopically homogeneous and isotropic multiphase materials.
Abstract: Variational theorems are established and applied to the derivation of bounds for the effective magnetic permeability of macroscopically homogeneous and isotropic multiphase materials. For reasons of mathematical analogy the results are also valid for the dielectric constant, electric conductivity, heat conductivity, and diffusivity of such materials. For the case of two‐phase materials, the bounds derived are the most restrictive ones that can be given in terms of the phase permeabilities and volume fractions. Comparison of present theoretical results with existing experimental data shows good agreement.
2,887 citations
2,831 citations