[PDF] Nonlinear Magnetization Dynamics Under Influence Of Oscillating Field eBook

Author : Philip E Wigen
Publisher : World Scientific
Page : 262 pages
File Size : 10,31 MB
Release : 1994-05-06
Category : Technology & Engineering
ISBN : 9814505498

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In this book, some of the principal investigators of the phenomena have reviewed their successes. The contributions include an overview of the field by H Suhl, followed by a detailed review of the high-power response of magnetic materials. Following that chapter, a number of authors review the phenomena for a variety of magnetic materials and pumping configurations.In the final chapter, evidence of another nonlinear effect is reviewed. Using a pulsed driving field, it is possible to excite a travelling spin wave. The nonlinear contributions will give rise to a “bunching” effect which compensates for the dispersive effects to produce a shape-preserving traveling wave pulse known as solitons.Ordered magnetic materials have provided a rich source for the investigation of nonlinear phenomena. These investigations have contributed much to our knowledge of the behavior of chaotic systems, as well as to a better understanding of the high-power response of the magnetic materials themselves.

Author : Isaak D. Mayergoyz
Publisher : Elsevier
Page : 479 pages
File Size : 34,23 MB
Release : 2009-04-20
Category : Mathematics
ISBN : 0080913792

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As data transfer rates increase within the magnetic recording industry, improvements in device performance and reliability crucially depend on the thorough understanding of nonlinear magnetization dynamics at a sub-nanoscale level. This book offers a modern, stimulating approach to the subject of nonlinear magnetization dynamics by discussing important aspects such as the Landau-Lifshitz-Gilbert (LLG) equation, analytical solutions, and the connection between the general topological and structural aspects of dynamics. An advanced reference for the study and understanding of nonlinear magnetization dynamics, it addresses situations such as the understanding of spin dynamics in short time scales and device performance and reliability in magnetic recording. Topics covered include nonlinear magnetization dynamics and the Landau-Lifshitz-Gilbert equation, nonlinear dynamical systems, spin waves, ferromagnetic resonance and pulsed magnetization switching. The book explains how to derive exact analytical solutions for the complete nonlinear problem and emphasises the connection between the general topological and structural aspects of nonlinear magnetization dynamics and the discretization schemes better suited to its numerical study. It is an exceptional research tool providing an advanced understanding of the study of magnetization dynamics in situations of fundamental and technological interest.

Author : A.G. Gurevich
Publisher : CRC Press
Page : 460 pages
File Size : 11,45 MB
Release : 2020-12-17
Category : Science
ISBN : 0429605757

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Written by two well-known researchers in the field, this useful reference takes an applied approach to high frequency processes including oscillations and waves in ferromagnets, antiferromagnets, and ferrimagnets. Problems evaluated include ferromagnetic and antiferromagnetic resonances, spin waves, nonlinear processes, and high frequency manifestations of interactions between the magnetic system and other systems of magnetically ordered substances as elastic waves and charge carriers. Unlike previous monographs on this subject, which are highly theoretical and written for very advanced readers, this book requires only an average college background in mathematics and experimental physics. It will be a valuable addition to the library of engineers and scientists in research and development for communications applications, and scientists interested in nonlinear magnetic phenomena. It also serves as an excellent introduction to the topic for newcomers in the field. Magnetization Oscillations and Waves not only presents results but also shows readers how to obtain them; most formulas are derived with so many details that readers can reproduce them. The book includes many summaries and tables and detailed references to significant work in the area by European researchers.

Author : Han Kyu Lee
Publisher :
Page : 130 pages
File Size : 41,67 MB
Release : 2017
Category :
ISBN : 9780355413908

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This dissertation explores the study of magnetization dynamics in a ferromagnetic thin film and nanoscale ferromagnets. In bulk ferromagnets, nonlinear interactions generally couple each spin wave eigenmode to a continuum of other available modes through multi-magnon scattering. The multi-magnon scattering can potentially limit an achievable amplitude of spin wave modes by pumping energy into other energy-degenerate modes. For example, two-magnon scattering process in the presence of impurities and defects is known to act as a channel of magnetic damping in ferromagnetic thin films. I present an observation of the two-magnon scattering in epitaxial La0.7Sr0.3MnO3 (LSMO) and LSMO/Pt thin films, investigate its impact on the evaluation of low magnetic damping in LSMO, and properties of spin transport through the LSMO/Pt interface for potential nanodevice applications.Magnetic damping is a critical parameter that determines the speed and energy efficiency of the magnetic nanodevice such as spin-torque memory and oscillators. In a nanomagnet, the geometric confinement breaks translational invariance of the system and discretizes the spin wave spectrum, which helps to suppress the kinematically allowed multi-magnon scattering. The suppression of multi-magnon scattering enables an unusual type of nonlinear interactions and excitation processes in nanoscale ferromagnets that are qualitatively different from that in bulk ferromagnets. In this regard, I report an observation of nonlinear resonant three-magnon scattering and its effect in the damping of nanoscale magnetic tunneling junctions (MTJs). The spectral lineshape of a spin wave resonance undergoing three-magnon scattering exhibits a minimum at the resonance frequency in sharp contrast to the amplitude maximum seen in the linear resonance regime. This unusual behavior arises because the damping parameter of a spin wave ceases to be frequency-independent and itself becomes a resonant function of the excitation frequency. Also, such resonant nonlinear damping dramatically alters the response of a nanomagnet to antidamping spin-torque in a counterintuitive way - the antidamping torque can increase the damping of a spin wave mode that undergoes the nonlinear resonant scattering.Lastly, I present an experimental demonstration of electric-field driven parametric excitation of a spin wave eigenmode in nanoscale MTJ. This work shows that the microwave electric field applied across the MTJ electrode efficiently couples to the out-of-plane component of oscillating magnetization via voltage-controlled magnetic anisotropy (VCMA) in the system. The threshold voltage of parametric excitation is found to be well below 1 Volt, which makes it attractive for magnonic nanodevices such as spin wave logic. The electric-field driven parametric excitation of magnetization is a versatile method for generating short-wavelength spin wave and thus results in this work pave the way towards energy-efficient excitation of magnetization dynamics in thin films of metallic ferromagnets and nanodevices based on magnetic multilayers.

Author : Jan Walleczek
Publisher : Cambridge University Press
Page : 444 pages
File Size : 15,1 MB
Release : 2006-04-20
Category : Science
ISBN : 1139427598

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The growing impact of nonlinear science on biology and medicine is fundamentally changing our view of living organisms and disease processes. This book introduces the application to biomedicine of a broad range of interdisciplinary concepts from nonlinear dynamics, such as self-organization, complexity, coherence, stochastic resonance, fractals and chaos. It comprises 18 chapters written by leading figures in the field and covers experimental and theoretical research, as well as the emerging technological possibilities such as nonlinear control techniques for treating pathological biodynamics, including heart arrhythmias and epilepsy. This book will attract the interest of professionals and students from a wide range of disciplines, including physicists, chemists, biologists, sensory physiologists and medical researchers such as cardiologists, neurologists and biomedical engineers.

Author : Harry Suhl
Publisher : OUP Oxford
Page : 208 pages
File Size : 29,64 MB
Release : 2007-06-21
Category : Science
ISBN : 0191523674

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Electrons in solids behave like microscopic bar magnets, and in certain solids these align to produce macroscopic magnetizations. This book deals with the dynamics of this magnetization field. It addresses questions of microscopic mechanism only to the extent that residual interactions of the magnetic moments with other degrees of freedom of the host solid affect the dynamics, particularly the dissipative aspects. Several of these damping mechanisms are evaluated here for their effect on the equations of the magnetization dynamics. This dynamics is intrinsically nonlinear. This is important in the applications, particularly magnetic recording, which involves very large motion of the magnetization, well beyond the validity of linearized (small motion) approximations or limited extensions thereof. Therefore nonlinear solution methods are emphasized, but with only minimal use of numerical simulation. The book should be useful to practitioners of magnetic recording, and to physicists studying magnetic phenomena.

Author : Gevorg Baghdasaryan
Publisher : Springer
Page : 0 pages
File Size : 13,93 MB
Release : 2024-07-08
Category : Science
ISBN : 9783031603068

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This book introduces the reader to methods of mathematical modeling and solving non-stationary (dynamic) problems of the theory of magnetoelasticity, as well as to give an idea of the wealth of physical effects caused by the interaction of electromagnetic and mechanical phenomena in magnetically active elastic thin bodies. The studies are mainly limited to a model of isotropic body under the assumption of small deformations. In the first chapter of the book, based on the basic connected nonlinear equations and relations of mechanics and quasi-static electrodynamics of continuum media, a system of equations of magnetoelasticity, surface conditions, and governing equations describing the behavior of disturbances in a magnetoactive medium interacting with an external magnetic field is obtained. On this basis, in Chapters 2 and 3, using the main equations and relations of magnetoelastic vibrations and stability of magnetically soft, thin plates and shells are obtained. By solving specific applied problems, a number of qualitative and quantitative results were identified, caused by the interaction of mechanical and magnetic phenomena in ferromagnetic thin bodies. An approximate formula is obtained to determine magnetohydrodynamic pressure on the oscillating surfaces of plate flowing by supersonic flow of perfectly conducting gas in the presence of magnetic field. This formula is the generalization of well-known formula obtained on the basis of the classical piston theory of gas dynamics in the case of magneto-gas-dynamic flow. On this basis, it became possible to solve complex problems of aeromagnetoelasticity. In the 4th and 5th chapters magnetoelastic processes in superconducting thin shells located in stationary and non-stationary magnetic fields are studied. Two-dimensional equations and corresponding conditions are obtained, which characterize vibrations and stability of superconducting cylindrical and spherical shells under the influence of the given magnetic field. By solving specific problems, the possibility of loss of both static and dynamic stability of thin superconducting bodies under the influence of external magnetic field has been established. The sixth chapter is devoted to mathematical modeling and investigation of issues of dynamics of magnetostrictive plates in magnetic fields (stationary and non-stationary) of several orientations. To study the processes of magnetoelastic interaction in the plate under consideration with complex physical properties of its material, the main postulates of the classical theories and methods were used. The influence of plate in-homogeneity on the processes under consideration was also studied. Dynamic processes in layered plates have been studied. It is shown that heterogeneity is sufficient to control optimally the studied dynamic processes, especially those that arise as a result of interaction. The last 7th chapter is devoted to the investigation of stability of dielectric thin plates in a supersonic flow of perfectly conducting gas in the presence of magnetic field. The problems were studied in both linear and nonlinear formulations. Based on the formula obtained by the authors specific problems of stability were solved. Influence of magnetic field on the flutter characteristics is studied.