scholarly journals Angular Dependence of the Ferromagnetic Resonance Parameters of [Ti/FeNi]6/Ti/Cu/Ti/[FeNi/Ti]6 Nanostructured Multilayered Elements in the Wide Frequency Range

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 433
Author(s):  
Sergei V. Shcherbinin ◽  
Andrey V. Svalov ◽  
Grigory Y. Melnikov ◽  
Galina V. Kurlyandskaya
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Rf Sputtering ◽  
Magnetization Vector ◽  
Wide Frequency Range ◽  
Easy Magnetization ◽  
Magnetic Field Sensors ◽  
Magnetic Susceptibility Tensor ◽  
Small Magnetic Field ◽  
Lifshitz Equation

Magnetically soft [Ti(6)/FeNi(50)]6/Ti(6)/Cu(500)/Ti(6)/[FeNi(50)/Ti(6)]6 nanostructured multilayered elements were deposited by rf-sputtering technique in the shape of elongated stripes. The easy magnetization axis was oriented along the short size of the stripe using deposition in the external magnetic field. Such configuration is important for the development of small magnetic field sensors employing giant magnetoimpedance effect (GMI) for different applications. Microwave absorption of electromagnetic radiation was experimentally and theoretically studied in order to provide an as complete as possible high frequency characterization. The conductor-backed coplanar line was used for microwave properties investigation. The medialization for the precession of the magnetization vector in the uniformly magnetized GMI element was done on the basis of the Landau–Lifshitz equation with a dissipative Bloch–Bloembergen term. We applied the method of the complex amplitude for the analysis of the rotation of the ferromagnetic GMI element in the external magnetic field. The calculated and experimental dependences for the amplitudes of the imaginary part of the magnetic susceptibility tensor x-component and magnetoabsorption related to different angles show a good agreement.

scholarly journals High Frequency Magnetoimpedance of FeNi/Cu/FeNi Sensitive Elements with Different Geometries

2009 ◽  
Vol 152-153 ◽  
pp. 373-376 ◽  
Author(s):  
Stanislav O. Volchkov ◽  
Andrey V. Svalov ◽  
G.V. Kurlyandskaya
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Finite Elements ◽  
Magnetic Anisotropy ◽  
Constant Magnetic Field ◽  
High Frequency ◽  
Complex Impedance ◽  
Rf Sputtering ◽  
Frequency Range

In this work magnetoimpedance (MI) behaviour was studied experimentally for Fe19Ni81(175 nm)/Cu(350 nm)/Fe19Ni81(175 nm) sensitive elements deposited by rf-sputtering. A constant magnetic field was applied in plane of the sandwiches during deposition perpendicular to the Cu-lead in order to induce a magnetic anisotropy. Sandwiches with different width (w) of FeNi parts were obtained. The complex impedance was measured as a function of the external magnetic field for a frequency range of 1 MHz to 700 MHz for MI elements with different geometries. Some of MI experimental data are comparatively analysed with finite elements numerical calculations data. The obtained results can be useful for optimization of the design of miniaturized MI detectors.

Propagation of electromagnetic waves in a warm plasma-filled cylindrical waveguide in the presence of an external magnetic field

1983 ◽  
Vol 29 (3) ◽  
pp. 383-392 ◽  
Author(s):  
Sanjay Kumar Ghosh ◽  
S. P. Pal
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electromagnetic Waves ◽  
Transverse Magnetic ◽  
Cylindrical Waveguide ◽  
Small Magnetic Field ◽  
Warm Plasma ◽  
Plasma Theory ◽  
The Waves ◽  
Constant External Magnetic Field

The propagation of electromagnetic waves in a plasma-filled cylindrical waveguide in the presence of a constant external magnetic field is investigated using warm plasma theory. It is found that the waves cannot be separated into transverse magnetic and transverse electric modes; only hybrid modes are propagated. Dispersion relations are derived for zero, finite and infinite magnetic fields. Frequency shifts for the wave propagation in the case of a small magnetic field are calculated.

scholarly journals Туннельные магниторезистивные элементы для датчиков магнитного поля

2019 ◽  
Vol 89 (11) ◽  
pp. 1732
Author(s):  
И.Ю. Пашенькин ◽  
М.В. Сапожников ◽  
Н.С. Гусев ◽  
В.В. Рогов ◽  
Д.А. Татарский ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Dielectric Layer ◽  
Mutual Orientation ◽  
Geometrical Parameters ◽  
Magnetic Field Sensors ◽  
Unidirectional Anisotropy ◽  
Magnetoresistive Effect

The technology of fabricating of chains of tunnel magnetoresistive (TMR) elements based on CoFe/Al2O3/NiFe nanostructures with pinning on the antiferromagnetic IrMn layer has been developed. The dependence of the magnetoresistance curves on the geometrical parameters of the laterally bounded TMR contacts, as well as on the mutual orientation of the external magnetic field and the axis of the unidirectional anisotropy of the fixed CoFe layer has been investigated. The resistance of the chains has been varied from several tens of kΩ to hundreds of MΩ, depending on the thickness of the tunnel dielectric layer. The magnitude of the magnetoresistive effect has been about 10–15%. The suggested technology can be used to make tunnel magnetic field sensors

scholarly journals Application of Magnetosomes in Magnetic Hyperthermia

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1320 ◽  
Author(s):  
Nikolai A. Usov ◽  
Elizaveta M. Gubanova
Keyword(s):  
Magnetic Field ◽  
Specific Absorption Rate ◽  
Magnetotactic Bacteria ◽  
Dipole Interaction ◽  
Magnetic Hyperthermia ◽  
Small Magnetic Field ◽  
Lifshitz Equation ◽  
Chain Axis ◽  
Rectangular Hysteresis Loop ◽  
A Chain

Nanoparticles, specifically magnetosomes, synthesized in nature by magnetotactic bacteria, are very promising to be usedin magnetic hyperthermia in cancer treatment. In this work, using the solution of the stochastic Landau–Lifshitz equation, we calculate the specific absorption rate (SAR) in an alternating (AC) magnetic field of assemblies of magnetosome chains depending on the particle size D, the distance between particles in a chain a, and the angle of the applied magnetic field with respect to the chain axis. The dependence of SAR on the a/D ratio is shown to have a bell-shaped form with a pronounced maximum. For a dilute oriented chain assembly with optimally chosen a/D ratio, a strong magneto-dipole interaction between the chain particles leads to an almost rectangular hysteresis loop, and to large SAR values in the order of 400–450 W/g at moderate frequencies f = 300 kHz and small magnetic field amplitudes H0 = 50–100 Oe. The maximum SAR value only weakly depends on the diameter of the nanoparticles and the length of the chain. However, a significant decrease in SAR occurs in a dense chain assembly due to the strong magneto-dipole interaction of nanoparticles of different chains.

scholarly journals The Microstructural Model of the Ferromagnetic Material Behavior in an External Magnetic Field

2021 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Anatoli A. Rogovoy ◽  
Oleg V. Stolbov ◽  
Olga S. Stolbova
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Domain Walls ◽  
Magnetic Energy ◽  
Spontaneous Magnetization ◽  
Magnetization Vector ◽  
Ferromagnetic Material ◽  
Extremum Problem ◽  
Material Behavior ◽  
Anisotropy Axis

In this paper, the behavior of a ferromagnetic material is considered in the framework of microstructural modeling. The equations describing the behavior of such material in the magnetic field, are constructed based on minimization of total magnetic energy with account of limitations imposed on the spontaneous magnetization vector and scalar magnetic potential. This conditional extremum problem is reduced to the unconditional extremum problem using the Lagrange multiplier. A variational (weak) formulation is written down and linearization of the obtained equations is carried out. Based on the derived relations a solution of a two-dimensional problem of magnetization of a unit cell (a grain of a polycrystal or a single crystal of a ferromagnetic material) is developed using the finite element method. The appearance of domain walls is demonstrated, their thickness is determined, and the history of their movement and collision is described. The graphs of distributions of the magnetization vector in domains and in domain walls in the external magnetic field directed at different angles to the anisotropy axis are constructed and the magnetization curves for a macrospecimen are plotted. The results obtained in the present paper (the thickness of the domain wall, the formation of a 360-degree wall) are in agreement with the ones available in the current literature.

scholarly journals Исследование связанной динамики магнитных вихрей в трехслойном проводящем наноцилиндре

2018 ◽  
Vol 60 (6) ◽  
pp. 1045
Author(s):  
С.В. Степанов ◽  
А.Е. Екомасов ◽  
К.А. Звездин ◽  
Е.Г. Екомасов
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Vortex Motion ◽  
Numerical Data ◽  
Sample Plane ◽  
Current Dependence ◽  
Magnetic Vortices ◽  
Lifshitz Equation ◽  
Spin Polarized ◽  
Stationary Vortex

AbstractSolving numerically the generalized Landau–Lifshitz equation, we have carried out the micromagnetic investigation of the dynamics of two dipole-coupled magnetic vortices in a trilayer nanocolumn under the action of the external magnetic field directed perpendicular to the sample plane and spin-polarized electric field. The possible existence of different regimes of vortex motion, depending on the polarized current, is demonstrated. The current dependence of the oscillation frequency for the case of stationary dynamics of coupled vortices with the same frequency has been established. The possibility of controlling the frequency of the stationary vortex motion and tuning the control current amplitude by the external magnetic field is shown. Using the analytical method for simplified description of the dynamics of coupled vortices, the current and magnetic-field dependences of the frequency have been obtained, which are qualitatively consistent with the numerical data.

scholarly journals Landau-Lifshitz equation of ferromagnetism with external magnetic field

2002 ◽  
Vol 72 (3) ◽  
pp. 299-316 ◽  
Author(s):  
P. Y. H. Pang ◽  
J. Xiao ◽  
F. Zhou
Keyword(s):  
Magnetic Field ◽  
Cauchy Problem ◽  
External Magnetic Field ◽  
Existence And Uniqueness ◽  
Blow Up ◽  
Uniqueness Of Solution ◽  
Energy Identity ◽  
Lifshitz Equation ◽  
The Cauchy Problem

AbstractIn this article, we prove the existence and uniqueness of solution for the Cauchy problem of the Landau-Lifshitz equation of ferromagnetism with external magnetic field. We also show that the solution is globally regular with the exception of at most finitely many blow-up points. An energy identity at blow-up points is presented.

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