Solid State Phenomena Vols. 233-234

Abstract: The technique of finite difference equations is used for analytical investigation of magnetization pattern in magnetic multilayers. The magnetic multilayers with equal magnetic layers and ferrimagnetic multilayers are considered. Heisenberg and biquadratic exchange interactions and uniaxial anisotropy are taken into account. The analytical dependencies of total magnetic moment on external magnetic field are obtained taking into account the strong interaction with the substrate. The significant difference in the behavior of magnetic moment is derived for ferrimagnetic multilayers with odd and even layers number.

Abstract: The problem of finding the Green's function of spin and electromagnetic waves in the sinusoidal superlattice is considered. An analytical expression for the spectral representation of the Green's function has been found in the form of ascending continued fractions, the particular denominators of which are ordinary continued fractions. The Green’s function in the-space has been found by the numerical Fourier transformation of the Greens’s function found in the spectral representation.

Abstract: The domain walls dynamics and generation and evolution of magnetic inhomogeneities of soliton type, emerging in a thin flat layer with the parameters of the magnetic anisotropy, which are different from other two thick layers of the five-layer ferromagnetic structure, were investigated.

Abstract: The magnetization dynamics of metal-organic crystals has been studied in low frequency AC magnetic field. Four modes of domain wall motion (Debye relaxation, creep, slide and over - barrier motion (switching)) were distinguished in [Mn^II(H(R/S)-pn)(H₂O)] [Mn^III(CN)₆]⋅2H₂O crystals. Debye relaxation and creep of the domain walls are sensitive to Peierls relief configuration controlled by crystal lattice chirality. Structural defects and periodical Peierls potential compete in the damping of the domain walls. Driving factor of this competition is ratio of the domain wall width to the crystal lattice parameter.

Abstract: The numerical method of Brown and La Bonte [1] is used to calculate both the total equilibrium energy and the magnetization distribution of one-dimensional Neel domain wall (DW). The continuous magnetization distribution of Neel DW is replaced by a discrete distribution for which the magnetostatic energy was calculated precisely using high-speed computer program.

Abstract: The morphology and magnetic characterization results of electroless deposited CoP coating on the copper microgrid with the mesh size of 50 microns are presented and discussed. The deposited coating is found to be well uniform by the thickness. Magnetic anisotropy in the plane of the grid has been studied by the hysteresis loops and the FMR spectra and discussed with the modeling of the grid as the frame grid system of magnetic tubes.

Abstract: Formation of a canted spiral magnetic order is studied in the framework of a mean-field approximation of the Hubbard model. It is revealed that this magnetic state can be stabilized under certain conditions in layered systemswith a relatively small interplane electron hopping. Example of an experimentally observed magnetic structure ofLa$_{2-x}$Sr$_x$CuO$_4$ is considered. It is shown that the canting magnetic order can be described in terms of a simplenon-relativistic band magnetism.

Abstract: The paper considers the second order precession of the magnetization vector in a perpendicular magnetized anisotropic ferrite plate with magnetoelastic properties. The boundaries of the precession regimes on the frequency and amplitude of the alternating field were defined. The features of the precession of the magnetization vector regimes associated with magnetoelastic properties were revealed.

Abstract: An influence of quenched nonmagnetic disorder on the phase transitions in the two dimensional antiferromagnetic Potts model with a number of spin state q=3 on a triangular lattice is calculated by the Monte-Carlo method. The systems with linear sizes L=20÷144 at spin concentrations p=1.00, 0.90, 0.80 are studied. By means of the fourth order Binder cumulant method, the inclusion of a quenched disorder as nonmagnetic impurities into a pure antiferromagnetic Potts model is shown to be the cause of the change of the first order phase transition into the second one.

Abstract: In this paper we propose a method to generate pure dark solitons by a periodic external field with a slowly varying frequency, which allows to control amplitude of the excited solitons and period of soliton trains. Our approach to generate dark solitons is based on the effect of autoresonance when the excited wave is phase-locked by the drive after the crossing the resonance. The resonant frequency and the threshold condition on the amplitude of the driving were found.