Spin Fluctuation Theory of Itinerant Electron Magnetism PDF Download

Author: Yoshinori Takahashi
Publisher: Springer
ISBN: 364236666X
Category : Science
Languages : en
Pages : 181

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Book Description
This volume shows how collective magnetic excitations determine most of the magnetic properties of itinerant electron magnets. Previous theories were mainly restricted to the Curie-Weiss law temperature dependence of magnetic susceptibilities. Based on the spin amplitude conservation idea including the zero-point fluctuation amplitude, this book shows that the entire temperature and magnetic field dependence of magnetization curves, even in the ground state, is determined by the effect of spin fluctuations. It also shows that the theoretical consequences are largely in agreement with many experimental observations. The readers will therefore gain a new comprehensive perspective of their unified understanding of itinerant electron magnetism.

Author: Toru Moriya
Publisher: Springer Science & Business Media
ISBN: 3642824994
Category : Technology & Engineering
Languages : en
Pages : 253

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Book Description
Ferromagnetism of metallic systems, especially those including transition metals, has been a controversial subject of modern science for a long time. This controversy sterns from the apparent dual character of the d-electrons responsible for magnetism in transition metals, i.e., they are itinerant elec trons described by band theory in their ground state, while at finite tem peratures they show various properties that have long been attributed to a system consisting of local magnetic moments. The most familiar example of these properties is the Curie-Weiss law of magnetic susceptibility obeyed by almost all ferromagnets above their Curie temperatures. At first the problem seemed to be centered around whether the d-elec trons themselves are localized or itinerant. This question was settled in the 1950s and early 1960s by various experimental investigations, in particular by observations of d-electron Fermi surfaces in ferromagnetic transition metals. These observations are generally consistent with the results of band calculations. Theoretical investigations since then have concentrated on explaining this dual character of d-electron systems, taking account of the effects of electron-electron correlations in the itinerant electron model. The problem in physical terms is to study the spin density fluctuati·ons, which are ne glected in the mean-field or one-electron theory, and their influence on the physical properties.

Author: Dieter Wagner
Publisher: Springer Science & Business Media
ISBN: 940115080X
Category : Science
Languages : en
Pages : 455

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Book Description
A summary of recent developments in theoretical and experimental studies of fluctuation effects in itinerant electron magnets, focusing on novel physical phenomena: soft-mode spin fluctuations and zero-point effects, strong spin anharmonicity, magnetic frustrations in metals, fluctuation effects in Invar alloys and low-dimensional systems. All of these may be important for novel high-technology applications.

Author: Nikolai B. Melnikov
Publisher: Springer
ISBN: 3319929747
Category : Science
Languages : en
Pages : 287

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Book Description
This book presents a theoretical framework for magnetism in ferromagnetic metals and alloys at finite temperatures. The objective of the book is twofold. First, it gives a detailed presentation of the dynamic spin-fluctuation theory that takes into account both local and long-wave spin fluctuations with any frequency. The authors provide a detailed explanation of the fundamental role of quantum spin fluctuations in the mechanism of metallic magnetism and illustrate the theory with concrete examples. The second objective of the book is to give an accurate and self-contained presentation of many-body techniques such as the functional integral method and Green's functions, via a number of worked examples. These computational methods are of great use to solid state physicists working in a range of specialties. The book is intended primarily for researchers, but can also be used as textbook. The introductory chapters offer clear and complete derivations of the fundamentals, which makes the presentation self-contained. The main text is followed by a number of well-organized appendices that contain a detailed presentation of the necessary many-body techniques and computational methods. The book also includes a list of symbols and detailed index. This volume will be of interest to a wide range of physicists interested in magnetism and solid state physics in general, both theoreticians and experimentalists.

Author: Jürgen Kübler
Publisher: Oxford University Press
ISBN: 019289563X
Category : Science
Languages : en
Pages : 541

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Book Description
This book, in the broadest sense, is an application of quantum mechanics and statistical mechanics to the field of magnetism. Under certain well described conditions, an immensely large number of electrons moving in the solid will collectively produce permanent magnetism. Permanent magnets are of fundamental interest, and magnetic materials are of great practical importance as they provide a large field of technological applications. The physical details describing the many electron problem of magnetism are presented in this book on the basis of the density functional approximation. The emphasis is on realistic magnets, for which the equations describing properties of the many electron problem can only be solved by using computers. The significant recent and continuing improvements are, to a very large extent, responsible for the progress in this field. Along with an introduction to the density functional theory, the book describes representative computational methods and detailed formulas for physical properties of magnets which include among other things the computation of magnetic ordering temperatures, the giant magneto-resistance, magneto-optical effects, weak ferromagnetism, the anomalous Hall and Nernst effects, and novel quasiparticles, such as Weyl fermions and magnetic skyrmions.

Author: Kazuo Nishimura
Publisher: Springer Nature
ISBN: 9811644578
Category : Business & Economics
Languages : en
Pages : 427

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Book Description
In recent years, problems such as environmental and economic crises and pandemics caused by new viruses have been occurring on a global scale. Globalization brings about benefits, but it can increase the potential risks of “systemic problems”, leading to system-wide disruptions. The coronavirus pandemic, declared on March 11, 2020, by the World Health Organization, has revealed social disparities in the form of a higher risk of death for people of low-socioeconomic status and has caused massive destruction of the economy and of globalization itself. Extensive efforts to cope with these challenges have often led to the emergence of additional problems due to the chain of hidden causation. What can be done to protect against such emerging challenges? Despite the resulting complexity, once these individual problems are considered as different aspects of a single whole, seemingly contradictory issues can become totally understandable, as they can be integrated into a single coherent framework. This is the integrationist approach in contrast to the reductionist approach. Situations of this kind are truly relevant to understanding the question, “What are creative complex systems?” This book features contributions by members and colleagues of the Kyoto University International Research Unit of Integrated Complex System Science. It broadens our outlook from the traditional view of stability, in which global situations are eventually stabilized after the impact of destruction, to “creative” complex systems.

Author: K.H.J. Buschow
Publisher: Elsevier
ISBN: 0080457657
Category : Technology & Engineering
Languages : en
Pages : 1361

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Book Description
Magnetic and superconducting materials pervade every avenue of the technological world – from microelectronics and mass-data storage to medicine and heavy engineering. Both areas have experienced a recent revitalisation of interest due to the discovery of new materials, and the re-evaluation of a wide range of basic mechanisms and phenomena. This Concise Encyclopedia draws its material from the award-winning Encyclopedia of Materials and Engineering, and includes updates and revisions not available in the original set -- making it the ideal reference companion for materials scientists and engineers with an interest in magnetic and superconducting materials. Contains in excess of 130 articles, taken from the award-winning Encyclopedia of Materials: Science and Technology, including ScienceDirect updates not available in the original set Each article discusses one aspect of magnetic and superconducting materials and includes photographs, line drawings and tables to aid the understanding of the topic at hand Cross-referencing guides readers to articles covering subjects of related interest

Author: Yoshiro Kakehashi
Publisher: Springer
ISBN: 9783642334023
Category : Science
Languages : en
Pages : 345

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Book Description
This book describes theoretical aspects of the metallic magnetism from metals to disordered alloys to amorphous alloys both at the ground state and at finite temperatures. The book gives an introduction to the metallic magnetism, and treats effects of electron correlations on magnetism, spin fluctuations in metallic magnetism, formation of complex magnetic structures, a variety of magnetism due to configurational disorder in alloys as well as a new magnetism caused by the structural disorder in amorphous alloys, especially the itinerant-electron spin glasses. The readers will find that all these topics can be understood systematically by means of the spin-fluctuation theories based on the functional integral method.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: T. Moriya
Publisher: Springer Science & Business Media
ISBN: 3642816398
Category : Science
Languages : en
Pages : 270

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Book Description
Speech by Toyosaburo Taniguchi Welcome my friends to the Third International Symposium, Division on the Theory of Condensed Matter, of the Taniguchi Foundation. The need is now greater than ever for Japan to consider how to strengthen and foster international understanding between nations, peoples and societies, and how to contribute towards the establishment of peace and prosperity in the world. For more than twenty years, I have been supporting a symposium on mathe matics in which distinguished scholars from allover the world have engaged in free discussions. In this symposium, all the participants live together in community style. I have heard from members of some of these study groups that this type of setup has helped to strengthen their ties and relationships with their colleagues on a personal basis. What developed in the mathematics group led me to reorganize and strengthen the Taniguchi Foundation only a few years ago through additional funding. In order to effectively translate the objectives of the Foundation into action with the funds available, it becomes necessary to select those fields which are not necessarily in the limelight of popular interest, which means those fields which, I am afraid, are low in funding. I would rather choose from modest unimpressive academic fields than for the Foundation, projects those that stand out in gaudy, gorgeous popular acclaim.