Magnetic resonance studies of three-layer FeNi/Bi/FeNi films

The interlayer coupling in three-layer FeNi/Bi/FeNi films is studied by electron magnetic resonance. The magnetic anisotropy at the permalloy–bismuth interface is shown to play a significant role in the formation of the magnetic state of the film structure. The interlayer coupling oscillation period is found to be about 8 nm. The interlayer coupling and the interface anisotropy and their temperature dependences are determined.     

Ferromagnetic and spin-wave resonance in Ni0.8Fe0.2/Dy1−x Cox bilayer films

The standing spin wave spectra of Ni_0.8Fe_0.2(1000–3000 Å)/(Dy_1?x Co_x(700 Å) bilayer exchange-biased films with two different (precompensation Dy_0.2Co_0.8 and postcompensation Dy_0.3Co_0.7) compositions of the hard magnetic layer are analyzed. Measurements are performed at room temperature. It is found that the effective magnetic layer thickness (d _eff=d ₀±Δd), which determines the wave vectors of the first modes in the spectrum, differs from the d ₀ value specified in film technology. The sign of |Δd| ～ 500 Å is governed by the composition of the DyCo hard magnetic layer.     

The Effect of Adhesion Interaction on the Mechanical Properties of Thermoplastic Basalt Plastics

The effect of temperature, adhesion time, and surface treatment of a reinforcing filler on the mechanical properties of thermoplastic basalt plastics based on a high-density polyethylene and a copolymer of 1,3,5-trioxane with 1,3-dioxolan is investigated. An extreme dependence for the adhesive strength in a thermoplastic-basalt fiber system is established and its effect on the mechanical properties of basalt plastics and the influence of the adhesion contact time on the adhesive strength in the system are clarified. The surface modification of basalt fibers in acidic and alkaline media intensifies the adhesion of thermoplastics to them owing to a more developed surface of the reinforcing fibers after etching. It is found that the treatment in the acidic medium is more efficient and considerably improves the mechanical properties of basalt plastics.     

Mössbauer studies on Tb x Fe1−x alloy films with perpendicular magnetic anisotropy

Amorphous ferrimagnetic Tb _x Fe_1?x films with perpendicular magnetic anisotropy and Tb _x Fe_1?x /NiFe exchange-coupled structures characterized by unidirectional anisotropy are obtained. The magnetic and chemical inhomogeneity of alloys of Tb _x Fe_1?x compensation composition is established on the basis of Mössbauer studies of these systems.     

An analysis of the mechanism of Kerr effect enhancement in Mn/Dy/Bi

A study is reported of the structural, magnetic, and magneto-optic properties of Mn/Dy/Bi films obtained by multilayer technology. The maximum Kerr rotation angle in such films is shown to be θ _k =2.25°. Possible reasons for such a large Kerr effect enhancement are considered, namely, an increase in the 6p–3d transition probability caused by symmetry distortion, polarization of the Bi6p band, and a change in the density of states near the Fermi level. The latter reason has been analyzed by simulating the electronic structure of Mn/Dy/Bi through superposition of Dy levels on the MnBi band structure. This approach has revealed possible additional transitions which may be induced by the presence of a Dy buffer and could contribute to the Kerr magneto-optic effect. Fiz. Tverd. Tela (St. Petersburg) 41, 91–97 (January 1999)     

Numerical simulation of the interaction of a transverse jet with a supersonic flow using different turbulence models

This paper presents a numerical simulation of the flow resulting from transverse jet injection into a supersonic flow through a slot nozzle at different pressures in the injected jet and the crossflow. Calculations on grids with different resolutions use the Spalart–Allmaras turbulence model, the k–ε model, the k–ω model, and the SST model. Based on a comparison of the calculated and experimental data on the wall pressure distribution, the length of the recirculation area, and the depth of jet penetration into the supersonic flow, conclusions are made on the accuracy of the calculation results for the different turbulence models and the applicability of these models to similar problems.     

Visualization of vortical flows in computational fluid dynamics

The concepts and methods of the visual representation of fluid dynamics computations of vortical flows are studied. Approaches to the visualization of vortical flows based on the use of various definitions of a vortex and various tests for its identification are discussed. Examples of the visual representation of solutions to some fluid dynamics problems related to the computation of vortical flows in jets, channels, and cavities and of the computation of separated flows occurring in flows around bodies of various shapes are discussed.     

Enhancement of the Kerr effect in magnetooptical DyFeCo/GeO carriers

The optimum parameters of a dielectric layer near the substrate in the interference multilayer structure are calculated. The calculations showed that this layer should have the index of refraction n∼3. The results are presented of measuring the Kerr angle of magnetooptical rotation in the multilayer structure, in which GeO films were used as dielectric layers for the first time. The maximum Kerr angle of rotation and magnetooptical quality observed in this system were 0.75° and 0.34°, respectively. These values exceed those inherent in the known information carriers, which demonstrates the advantage of this structure for use in magnetooptical discs.     

Interlayer interactions in FeNi/Bi/FeNi trilayers

Interlayer interactions in FeNi/Bi/FeNi films are studied experimentally. It is established by SQUID magnetometry and magnetic resonance investigations that the interlayer interaction in these films is determined by the bismuth spacer thickness and temperature. A giant magnetoresistance effect is observed in the investigated trilayers.