Capabilities of Magnetic Pseudoresonance in Studies of Thin Ferromagnetic Films with Uniaxial Magnetic Anisotropy

Technical Physics - Possibilities of magnetic pseudoresonance (a non-resonance peak of magnetic susceptibility) were studied and compared with the ferromagnetic resonance (FMR) in measuring the...     

Micromagnetic Structures Induced by an Inhomogeneous Electric Field in Magnetically Uniaxial Films with a Flexo-Magnetoelectric Effect

Physics of the Solid State - The features of the manifestation of the flexo-magnetoelectric effect in magnetically uniaxial films under the local influence of an electric field on their surface are...     

A Geometric Interpretation of the Effective Uniaxial Anisotropy Field in Magnetic Films

It is shown that the effective uniaxial anisotropy field that is usually applied in thin magnetic films (TMFs), which is noncollinear to the magnetization vector, is insufficient for deeper understanding of these processes, although it explains many physical processes in films. The analysis of the magnetization discontinuity in films under certain conditions yields the component of the effective uniaxial anisotropy field collinear to the magnetization vector. This component explains the magnetization discontinuity and allows one to speak of the total effective uniaxial anisotropy field in TMFs.     

Interaction of a Magnetic Vortex with Magnetic Anisotropy Nonuniformity

Journal of Experimental and Theoretical Physics - The problem of propagation of a magnetic inhomogeneity in the form of a magnetic vortex near a defect simulated by a crystallite with uniaxial...     

Magneto-Optical Parameter Q for Structures with Uniaxial Optical Anisotropy

Journal of Experimental and Theoretical Physics - This paper is devoted to the development of reflection magneto-optical ellipsometry. We have solved the inverse problem for structures with...     

Magnetic Phases and Inhomogeneous Micromagnetic Structures in a Ferrite Garnet Film with Orientation (210)

Possible magnetic states of a cubic ferromagnet with a uniaxial anisotropy induced along the [210] direction are theoretically investigated. It is demonstrated that the orientation phase diagram of a magnet is nontrivial and admits the existence of three types of magnetic phases that differ in transformational properties and the presence of quintuple points, isostructural phase transitions, etc. It is found that magnetic inhomogeneities, regardless of the values of parameters of the matter, have a common structure: they correspond to 180-degree domain boundaries with a noncircular trajectory of the magnetization vector. The features of homogeneous and inhomogeneous magnetic states, found in these materials, make it possible to explain the manifestation of a flexomagnetoelectric effect in them.     

Micromagnetic Simulation of the Magnetoelastic Effect in Submicron Structures

Physics of the Solid State - The effect of deformations on magnetic nanoparticles of elliptic, square, and triangular shapes is simulated. The distribution of the magnetization of such particles is...     

Vortex-like Structures at the Defects of Uniaxial Films

Physics of the Solid State - Magnetic inhomogeneities formed at columnar defects of potential-well type in uniaxial films are theoretically studied. It is shown that under some conditions,...     

Heat-Treatment Induced Magnetic Anisotropy of GaMnSb Films

Conditions and mechanisms of controlled variation of the magnetic anisotropy of GaMnSb films containing magnetic MnSb nanoinclusions by means of heat treatment have been determined. For this purpose, the temperature and magnetic-field dependences of the magnetic moments of samples before and after thermal annealing were measured using a SQUID magnetometer. It is established that the heat treatment of GaMnSb films leads to a significant increase in the values of characteristics determined by the magnetic anisotropy, including the growth of blocking temperature (from 95 to 390 K) and the magnetic anisotropy field (from 330 to 630 Oe). Results of transmission electron microscopy investigation indicate that a change in the magnetic anisotropy of GaMnSb films as a result of their thermal annealing can be related to a transition of the crystalline structure of magnetic MnSb nanoinclusions from hexagonal (space group P6₂/mmc) to cubic (space group F-43m).     

Dynamic Charged Structures in Nematics with Negative Anisotropy of Electroconductivity

Journal of Experimental and Theoretical Physics - I would like to express my respect to Dzyaloshinski—co-author Method of Quantum Field Theory in Statistical Physics (Englewood Cliffs:...     

Preparation of Fe/Pt Films with Perpendicular Magnetic Anisotropy

We have investigated the microstructures and magnetic properties of L1₀ ordered equi-atomic FePt thin films prepared by ion beam sputtering and subsequent annealing. It is observed from X-ray reflectivity and X-ray diffraction measurements that the mixing at Fe/Pt interfaces starts to occur with annealing and leading to the FePt alloy phase formation. The rapid increase in the coercivity values above 275°C, obtained from vibrating sample magnetometer (VSM) measurements, confirms the formation of the ordered L1₀ FCT FePt phase.     

Magnetic Anisotropy Induced by Orbital Occupation States in La_(0.67)Sr_(0.33)MnO_3 Films

Interface engineering is an effective and feasible method to regulate the magnetic anisotropy of films by altering interfacial states between films.Using the technique of pulsed laser deposition,we prepared La_(0.67)Sr_(0.33)MnO_3(LSMO) and La_(0.67)Sr_(0.33)MnO_3/SrCoO_(2.5)(LSMO/SCO) films on(110)-oriented La_(0.3)Sr_(0.7)Al_(0.65)Ta_(0.35)O_3 substrates.By covering the SCO film above the LSMO film,we transformed the easy magnetization axis of LSMO from the [001] axis to the [110] axis in the film plane.Based on statistical analyses,we find that the corresponding Mn-Mn ionic distances are different in the two types of LSMO films,causing different distortions of Mn-O octahedron in LSMO.In addition,it also induces diverse electronic occupation states in Mn~(3+) ions.The eg electron of Mn~(3+)occupies 3 z~2-r~2 and x~2-y~2 orbitals in the LSMO and LSMO/SCO,respectively.We conclude that the electronic spin reorientation leads to the transformation of the easy magnetization axis in the LSMO films.     

Micromagnetic Modeling of Spin-Wave Excitations in Corrugated YIG Films

Physics of the Solid State - In this paper, we study the features of the spin-wave excitation spectrum in a YIG film with a thickness of 0.4 μm and a magnetization of 1.1 kG corrugated due to...     

Spectral Photosensitization of Optical Anisotropy in Solid Poly(Vinyl Cinnamate) Films

The possibility and features of formation of sensitized photoinduced optical anisotropy in amorphous films of poly(vinyl cinnamate) and its derivative poly(vinyl-4-metoxicinnamate) under the action of polarized light (including light that is not absorbed by polymer macromolecules themselves) have been investigated. It is found that the effect of induced optical anisotropy is based on the transfer of electron excitation energy from donor (sensitizer) molecules to acceptor molecules and is observed in the course of phototopochemical biomolecular cyclization reaction of cinnamate fragments in polymer macromolecules. The detected photoinduced anisotropy in solid films of poly(vinyl cinnamate) and its derivative poly(vinyl-4-metoxicinnamate) ensures sensitized photo-orientation of low-molecular thermotropic liquid crystals.     

磁性单层膜磁学性质的Monte Carlo模拟

采用类Ising模型,利用Monte Carlo方法研究了磁性单层膜中退磁性偶极作用和铁磁性交换作用对系统磁学性质的影响.结果显示,随着偶极相互作用的增加,系统在低温下的磁化出现平台现象,此时磁化曲线可分为2个阶段,在低外场下,温度升高,系统易磁化,在高外场下则反之.这种新奇的磁化行为导致系统的磁熵变在低温低外场下出现大于零的反常行为.在模拟过程中,对长程力作用采用了比较精确的处理方法.     

Simulation of Vortex Convection in a Compressible Viscous Flow with Dynamic Mesh Adaptation

In this work, vortex convection is simulated using a dynamic mesh adaptation procedure. In each adaptation period, the mesh is refined in the regions where the phenomena evolve and is coarsened in the regions where the phenomena deviate since the last adaptation. A simple indicator of mesh adaptation that accounts for the solution progression is defined. The generation of dynamic adaptive meshes is based on multilevel refinement/coarsening. The efficiency and accuracy of the present procedure are validated by simulating vortex convection in a uniform flow. Two unsteady compressible turbulent flows involving blade-vortex interactions are investigated to demonstrate further the applicability of the procedure. Computed results agree well with the published experimental data or numerical results.