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Anomalous magneto-elastic property of interacting multipoles is investigated with account of fluctuation effects. We use two complementary methods both of which deal with fluctuation effects beyond the mean-field theory. One is to take the two-site model which has a multipolar coupling between them and to solve the model exactly. The other approach is to take the effective medium theory for the lattice system. It takes into account fluctuations up to O(1/zn) around the mean-field theory where zn is the number of interacting neighbors. In the latter approach, it is found that some components of the local strain susceptibility increase as the fluctuation is suppressed by a magnetic field. This leads to increase of corresponding uniform strain susceptibility, and softening of the corresponding elastic constant.

Ultrasonic investigations of the spin-Peierls compound are reported and analyzed on the basis of magneto-elastic coupling. Sound velocity anomalies reported recently for pure or doped CuGeO 3 compounds can be interpreted using a simple theoretical model. We conclude that such anomalies are completely independent of the existence of the spin-Peierls transition reported for the pure compounds.

Measurements of the elastic tensor elements and magnetostriction constants in the temperature range of 100 to 300 K are reported for Mn x Fe 3- x O 4 ( x = 1.05, 1.7 and 1.8), from which the magneto-elastic anisotropy K ′ 1 and the coefficients B 1 and B 2 are deduced. The magneto-elastic anisotropy contribution to K 1 is found to be small compared with the magnetocrystalline anisotropy.

This paper studies magneto-elastic Rayleigh waves on the surface of orthotropic cylinder of varying density. Solving three dimensional magneto-elastic equations frequency equations for axial waves are derived.

The magneto-elastic torsional wave in a bar under initial stress is studied. Most of the equations have been formulated on Biot’s incremental deformation theory and the initial stress has been taken in the form of uniform tension. Two cases have been considered: first when the material of the rod is homogeneous and second when it is non-homogeneous. In both the cases frequency equations for the wave have been calculated

This paper investigates magneto-elastic torsional waves in a composite non homogeneous cylindrical shell under initial stress. The non homogeneous character of the shell is due to the variable elastic constants C/sub ij/ and the variable density rho. The composite form of the shell is due to the combination of orthotropic elastic material and visco-elastic material of general linear type. Frequency equation for the said wave has been derived.

Un recuit approprie provoque une augmentation de l'amplitude des ondes magneto-elastiques. Mais la fluctuation de l'onde magnetoelastique avec la distance le long du ruban devient plus grande par recuit

The paper is concerned with the derivation of a two dimensional theory of magneto-elasticity of anisotropic solids with cylindrical hole. The theory has been developed in complex variable formalism and illustrated by considering a particular type of magnetic field.

In this paper we deduce the magneto-elastic system of equations in the three-dimensional case. As an application we study the propagation of a weak discontinuity when a strong discontinuity also occurs.

The electro-magnetic equations of Maxwell and the equations of elasticity have been used to investigate the disturbances in an elastic bar acted upon by a magnetic field.

The paper is concerned with the investigation of the plane Lamb's problem in which a line load is suddenly applied on a magneto-elastic initially stressed conducting half-space bounded by a plane. The results obtained in this investigation are in agreement with the corresponding results of the classical plane Lamb's problem when the semispace is supposed to be initially unstressed and non-magnetic.

The present note is an attempt to discuss the disturbances in a cylinder characterised by a visco-elasticity of general linear type, which is subjected to a magnetic field.

The influence of a uniform external magnetic field on the propagation of harmonic waves in a perfectly conducting elastic plate extending to infinity in vacuum, with its plane boundaries free of mechanical tractions, has been studied. With the plane of the field and the direction of wave propagation being normal to the plate, it is found that the effects of electromagnetic radiation into the adjoining free space cannot be neglected in the case of waves polarized in the plane. When the field is aligned with the direction of propagation, the maximum influence appears to be on long flexural waves, whereas if the field is normal to the plate then the effect is very much pronounced on long plate waves, and the flexural waves propagate almost with Alfvén velocity.

The temperature dependence of the isotropic component of the basal-plane forced magnetostriction of terbium was measured between applied fields 17 500–19 500 oe. A peak value of − 18·5 × 10−9/oerst...

The appearance of an electromotive force at the terminals of a vibrating rod or wire of magnetic material was investigated. It was concluded from experiments somewhat more simple and direct than those employed by other investigators that the effect was due to changes in the state of circular magnetization accompanying the variations of stress. The results suggested problems for more intensive investigation and applications of possible practical value.

The propagation of plane waves in an electrically conducting cosserat medium placed in a magnetic field is investigated. The constitutive equations of cosserat elasticity developed recently byParia have been combined with the field equations of electromagnetism to obtain the basic equations for the problem. The results obtained in this investigation are in agreement with the corresponding results on magneto-elastic plane waves in Hookean solids when the cosserat constants are supposed to be absent.

The object of the present paper is to investigate the so-called planeLamb's problem in an initially stressed magneto-elastic semi-space bounded by a plane. The results obtained in this investigation are in agreement with the corresponding results of the classical planeLamb's problem when the semi-space is supposed to be initially unstressed and non-magnetic.

Investigated is the steady state response to moving loads in an initially stressed magneto-elastic half-space bounded by a plane. The results obtained in this problem are in agreement with the corresponding classical results when the half space is supposed to be initially unstressed and non-magnetic.

Die Fortpflanzung elastischer Wellen in einem anfanglich spannungsbelasteten, unbegrenzten, leitenden Medium in Anwesenheit eines magnetostatischen Feldes wird mittels einer linearen Theorie untersucht, die von einer nichtlinearen Elastizitatstheorie abgeleitet wird. Die ebene, periodische Wellenlosung wird fur den Fall erhalten, dass der ideale Leiter sich in einem gleichformigen magnetischen Feld befindet. Drei verschiedene anfangliche Spannungszustande werden in Betracht gezogen: Wenn der anfangliche Spannungszustand als Norm betrachtet wird, dann fuhrt das magnetische Feld zu einer gegenseitigen Beeinflussung zwischen den Longitudinal- und Transversalwellen, wahrend die Wellengeschwindigkeiten sowohl vom Magnetfeld als auch von der Anfangsspannung abhangen. Es wird gezeigt, dass das Magnetfeld manchmal die Wellengeschwindigkeit so beeinflusst, dass der Effekt des anfanglichen Spannungszustandes aufgehoben wird.

The paper deals with the propagation of waves in a magneto-elastic initially stressed conducting layer. The wave velocity equation obtained is in agreement with the classical result of Rayleigh and Lamb when the layer is initially unstressed and the magnetic field isabsent.

Der Maxwellsche Ansatz fur die Spannung im Innern eines homogenen isotropen elastischen Mediums in Gegenwart eines statischen Magnetfeldes wird aus der Bewegungsgrundgleichung der Magnetoelastizitat abgeleitet. Man stellt fest, das das Medium im allgemeinen seine Isotropieeigenschaft verliert. Es wird sodann die Fortpflanzung von Torsionswellen in einem massiven Kreiszylinder und in einem kreiszylindrischen Rohr, beide Male unter der Annahme eines konstanten axialen Magnetfeldes, betrachtet, wobei die Kenntnis der Maxwell-Spannungen wesentlich ist. The Maxwellian stress set up inside a homogeneous isotropic elastic medium in the presence of a static magnetic field has been derived from the fundamental equation of motion of magneto-elasticity. It has been observed that the medium loses its isotropy property in general. Propagation of torsional waves in a solid circular cylinder and in a circular cylindrical tube both in the presence of a constant axial magnetic field have been considered, where knowledge of the Maxwell stresses are essential.

The magneto-elastic anisotropy due to edge and screw dislocations on commonly observed slip planes in Ni(100), Fe(100), and Ni-Fe(100) single crystal films has been calculated using a single domain treatment. The magnetization is assumed to be constrained to the film plane by magneto-static forces. The results show that both dislocation types give dominantly uniaxial anisotropies in all three materials. The magnitude of the anisotropy varies inversely with distance from the core and in a complex fashion around the core. Also the easy direction varies around the core. The data are presented for the three materials and the qualitative agreement with magnetization ripple observations is shown to be good. Es wird die durch Stufen- und Schraubenversetzungen hervorgerufene magnetoelastische Anisotropie von normalerweise beobachteten Gleitebenen in Ni(100)-, Fe(100)- und Ni- Fe(100)-Einkristallschichten mit einer Ein-Domanenbehandlung berechnet. Dabei wird angenommen, das die Magnetisierung durch magnetostatische Krafte auf die Schichtebene beschrankt ist. Die Ergebnisse zeigen, das beide Versetzungsarten in allen drei Materialien vorherrschend uniaxiale Anisotropien ergeben. Die Grose der Anisotropie andert sich invers mit dem Abstand vom Kern und in einer komplexen Weise um den Kern herum. Auch die leichte Richtung variiert um den Kern herum. Die Werte fur die drei Materialien werden angegeben und eswird gezeigt, das die qualitative Ubereinstimmung mit Ripple-Beobachtungen der Magnetisierung gut ist.

The paper is concerned with the investigation of the magneto-elastic waves and disturbances in initially stressed conducting media. Firstly, (a) the steady state response to moving loads in a magneto-elastic initially stressed conducting medium under an uniaxial tension has been discussed. Secondly, (b) the Lamb's problem corresponding to a line load suddenly applied in a magneto-elastic initially stressed conducting half-space bounded by a plane under uniaxial tension has been investigated. The final results obtained in both cases are in agreement with the corresponding classical problems when the initial tension is zero and the magnetic field is absent.

The paper deals with the problem of determining the displacement, magnetic field, and the torsional stress of an aelotropic cylinder executing the torsional vibration in a magnetic field.

Using GDQ method, the radial and circumferential stresses in an annular FGM plate with a uniform thickness under a transverse axisymmetric load is investigated. It is assumed that a uniform radial magnetic field acts on the top surface of the plate. The modulus of elasticity E and the magnetic permeability coefficient μ of the plate along its thickness are assumed to vary according to the volume distribution function. The Poisson's ratio ν is considered to be constant. Based on the classical plate theory (CPT), equilibrium equations are deduced and the displacement fields are determined. The radial and circumferential stresses as well as transverse and radial displacements are obtained accordingly. The effect of volume fraction function power m on the maximum deflection in the absence and presence of the magnetic field is also investigated. Moreover, the effect of t/a and b/a ratios on displacements, stresses, induction magnetic field intensity and the resulting Lorentz force are also investigated. According to the results, for different points along the radial direction, the application of radial magnetic field to the top surface of the plate completely changes the state of stress in both tangential and radial directions, resulting in tensile and compressive stresses in these two directions. The results also indicate that in presence of magnetic field, the plate displacement and stress components are lowered considerably.

The relationship between magnetic flux density B , and stress σ in ferrites is presented. The origin of the Villari effect and its technical importance is discussed. It is shown that the position of the Villari point and piezomagnetic sensitivity depend on the same properties of a material as those governing the B ( H ) relation.

The rhombohedral lattice parameters of pure V2O3 show anomalous behaviour in the high temperature region. The change in the rate of expansion of the rhombohedral angle αR occurs at 533 K where the lattice constant aR reaches a minimum. The sharp dip at 533 K in the aR curve can be correlated with the peak observed in recent small angle scattering of neutrons and might be due to some dynamic magneto elastic effect.

In antiferromagnets (AF) the exchange interaction enhances the influence of hyperfine and spin-orbit interactions upon statics and dynamics of the magnetic system. Therefore the use of small anysotropy AF's instead of ferrites can sometimes improve the technical performance of the devices based on magneto elastic and other phenomena.

Ferromagnetic resonance at 102.5 GHz has been observed in the rare-earth intermetallic alloy ${\mathrm{Tb}}_{85}$${\mathrm{Y}}_{15}$ and the data have been compared with the theory of Cooper, including the magneto-elastic effects in the frozen-strain model. Based on a N\'eel temperature of 204\ifmmode^\circ\else\textdegree\fi{}K, parameters which give the best fit to the data are: axial anisotropy ${P}_{2}S=15.5$ \ifmmode^\circ\else\textdegree\fi{}K/ atom and magneto-elastic constant ${D}^{\ensuremath{\gamma}}=1.7$ \ifmmode^\circ\else\textdegree\fi{}K/ atom. These compare to the values for pure Tb: ${P}_{2}S=18.2$ \ifmmode^\circ\else\textdegree\fi{}K/ atom and ${D}^{\ensuremath{\gamma}}=1.7$ \ifmmode^\circ\else\textdegree\fi{}K/ atom. A physical explanation for the observed dependence of ${P}_{2}S$ on the concentration of a nonmagnetic diluent (Y) is given.