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Mean-field continual model of Ruderman--Kittel--Kasuya--Yosida (RKKY) magnetism in thin films and wires is considered. The spatial distribution of the magnetization is described by the nonlinear integral equation. The magnetization distribution over the film thickness or the wire diameter is close, correspondingly, to the parabolic or Gaussian one. The dependence of the Curie temperature on the film thickness, and temperature dependencies of the average film and wire magnetizations are determined. Index Terms--Magnetic films, magnetic semiconductors.

Sputtered [(Pt-Co).sub.n]-FeMn multilayers exhibit both perpendicular magnetic anisotropy and exchange bias at room temperature. Their magnetic properties after in-plane and perpendicular-to-plane magnetic annealing have been studied by means of extraordinary Hall effect and magnetic force microscopy or polar Kerr microscopy. A crossover from in-plane to perpendicular anisotropy was observed as a function of number of repeats n. The dynamics of magnetization switching has been investigated on both sides of the hysteresis loops. A clear asymmetry exists in the dynamics depending whether the field is parallel or antiparallel to the exchange bias field. Similarly, strong differences in the domain patterns at the coercive field were observed. Exchange-biased (Pt-Co)-Pt-(Pt-Co)-FeMn spin-valves were also investigated. Well-separated hysteresis loops were associated with the 'soft' and pinned components of the stack. These structures were used to study the interlayer coupling through the Pt spacer. Index Terms--Exchange bias, interlayer coupling, magnetic switching dynamics, perpendicular magnetic anisotropy.

This paper presents a method for modeling magnetoelastic material where magnetic and mechanical (elastic) phenomena are coupled in consequence of magnetic forces and magnetostriction. First, the basic equations and constitutive laws are derived on the basis of a continuum description of magnetoelastic material. Further, the numerical implementation by using the finite-element method is discussed and illustrated by means of an application example. Index Terms--Magnetic forces, magnetoelasticity, magnetostriction.

A fast differential equation approach for the Della Torre, Oti, and Kadar model has been extented to the complete moving hysteresis (CMH) model. Also, a cobweb technique for calculating the CMH model is also presented. The two techniques are contrasted from the point of view of flexibility and computation time. Index Terms--Cobweb, complete moving hysteresis model, hysteresis, magnetic modeling, Preisach model.

The time-domain performance of a number of absorbing boundary conditions invoked on the boundary of a domain of computation, as well as of a perfectly matched layer surrounding such a domain, is carried out for a test configuration for which analytic expressions for the relevant field quantities exist. The test configuration consists of a small loop antenna radiating into a homogeneous, isotropic half-space. On the planar boundary of this half-space, either an absorbing boundary condition is invoked or a perfectly matched layer is started that is truncated at some finite depth of penetration. For a loop parallel to the boundary, closed-form analytic expressions for all field components of the spuriously reflected field are presented for all truncation conditions involved. A number of important features show up that might he masked in purely numerical implementations of the procedures under consideration. Index Terms--Absorbing boundary conditions, computational modeling, perfectly matched layers.

An analytical approach is developed to predict the inverter high frequency pulse width modulation (PWM) switching caused eddy-current losses in a permanent magnet brushless dc motor. The model uses polar coordinates to take curvature effects into account, and is also capable of including the space harmonic effect of the stator magnetic field and the stator lamination effect on the losses. The model was applied to an existing motor design and was verified with the finite element method. Good agreement was achieved between the two approaches. Hence, the model is expected to be very helpful in predicting PWM switching losses in permanent magnet machine design. Index Terms - Eddy-current loss, permanent magnet brushless dc motors, pulse width modulation switching, space harmonics.

The crossover of the hysteresis branches in the classical coherent rotation model is analyzed. The analysis is extended when the truncated Stoner-Wohlfarth astroid is used. The physical explanation of the crossover occurrence is given. More accurate expressions of the anisotropy free energy density are required to better describe the behavior of the system when the angle between the easy axis and the magnetic moment of the particle is near 90[degrees]. A simple approximate formula for the hysteresis loop branches, which are in good agreement with those obtained when the discussed corrections are made, is given. The effect of the use of the Stoner-Wohlfarth astroid in the calculus of the equilibrium state in some vector Preisach-type models is analyzed. Index Terms - Magnetic anisotropy, micromagnetics, particulate recording media, Preisach model, Stoner-Wohlfarth model.

An optical fiber imaging system helps evaluate the influences of magnetic and gas dynamics on the arc chamber of miniature circuit breakers. A one-dimensional flow model, based on magnetic calculations, enables the analysis of these influences. Magnetic data, in conjunction with conductivity and pressure data, indicate factors affecting the arc chamber environment such as steel, plasma jet and formation of pressure waves.

We present a new finite element method in micromagnetics. The magnetization is linearly interpolated within each tetrahedral element and the magnetostatic interaction is accurately obtained by integration. The equilibrium magnetizations at the nodal points can be found by minimizing the total energy of the system. Two different minimization schemes are compared.

The physical structure of the magnetic electrodes of Co-[Al.sub.2][O.sub.3]-Co magnetic tunnel junctions has been investigated by means of [sup.59]Co nuclear magnetic resonance and X-ray diffraction. Junctions sputtered on FeMn have an essentially fcc (111)-oriented bottom electrode, while all top electrodes and the bottom electrodes of junctions sputtered on Ta are polyphase and polycrystalline. The specifics of the electronic structure of the electrode crystal phases can explain the extra features and asymmetry in the conductance-versus-bias behavior observed in FeMn-based junctions. Index Terms--Electronic structure, magnetic tunnel junctions, NMR, structural analysis.

The normal modes of an inhomogeneons thin film are obtained by diagonalization of the perturbed Hamiltonian. The resulting modes are mixtures of the spin-wave modes and the uniform mode. We find that the ferromagnetic resonance intensity spectrum of the diagonalized system has a Lorentzian profile, and that the results correspond to the two-magnon model for weak perturbations. For stronger perturbations, the density of states is smoothed, and the spectrum becomes asymmetric due to the low-frequency cutoff of the spin-wave manifold. The technique is expected to be valid for perturbation amplitudes that are large enough to invalidate the assumptions of the two-magnon model. Index Terms--Damping, ferromagnetic resonance, magnetic thin films, two-magnon model.

This paper presents a way to relate two standard models for magnetomechanical hysteresis - the Sablik-Jiles-Atherton model and the Schneider-Cannell-Watts model - while at the same time presenting physical models for the asymmetry in magnetic property behavior under tensile and compressive stress in steel, including, for oH processes, the presence of an extremum in the dependence of magnetic properties on tensile stress, an effect which is sometimes known as the Villari effect.

Simulations of magnetic and magnetoelastic behavior based on micromagnetic theory exhibit hysteresis. These magnetic systems have a highly nonlinear character involving short and long range fields. Computational results are presented and the role of various energetic contributions assessed and predicted using methods of contemporary nonlinear analysis.

A ferromagnetic, planar spin-model with random anisotropies in two dimensions is used to simulate thermally activated processes in exchange-coupled, two-phase permanent magnets by Monte Carlo dynamics. Simulations of hysteresis and slow relaxation processes at finite temperature are reported. The model displays exchange-spring behavior, anomalous viscosity along recoil loops, and thermal remagnetization in qualitative accord with experimental findings on spring magnets. The anomalous relaxation of the model can be explained by shrinking of subcritical interaction domains along the recoils. It is argued that disorder is important for the observability of anomalous viscosity in materials, which undergo magnetic reversal by nucleation and growth of interaction domains. Index Terms--Magnetization processes and modeling, viscosity, spring magnets, thermal remagnetization.