Spin Fluctuation Theory of Itinerant Electron Magnetism

Spin Fluctuation Theory of Itinerant Electron Magnetism PDF

Author: Yoshinori Takahashi

Publisher: Springer

Published: 2013-04-09

Total Pages: 190

ISBN-13: 364236666X

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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.

Spin Fluctuations in Itinerant Electron Magnetism

Spin Fluctuations in Itinerant Electron Magnetism PDF

Author: Toru Moriya

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 253

ISBN-13: 3642824994

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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.

Theory of Itinerant Electron Magnetism

Theory of Itinerant Electron Magnetism PDF

Author: Jürgen Kübler

Publisher: Oxford University Press

Published: 2000-08-17

Total Pages: 494

ISBN-13: 0198500289

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This book, in the broadest sense, is an application of quantum mechanics and statistical mechanics to the field of magnetism. The microscopic theory of many electron systems, which provide the physical understanding of magnetism, is presented in detail. Emphasis is given on how to solve the equations numerically by means of suitable computer programmes, and how to apply them to practical problems arising in mechanical engineering or material sciences.

Itinerant Electron Magnetism: Fluctuation Effects

Itinerant Electron Magnetism: Fluctuation Effects PDF

Author: Dieter Wagner

Publisher: Elsevier

Published: 1998-08-31

Total Pages: 478

ISBN-13: 9780792352037

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Proceedings of the NATO Advanced Research Workshop on Itinerant Electron Magnetism: Fluctuation Effects & Critical Phenomena, Moscow, Russia, September 15-19, 1997

Lecture Notes On Electron Correlation And Magnetism

Lecture Notes On Electron Correlation And Magnetism PDF

Author: Patrik Fazekas

Publisher: World Scientific

Published: 1999-01-25

Total Pages: 794

ISBN-13: 9814499625

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This volume attempts to fill the gap between standard introductions to solid state physics, and textbooks which give a sophisticated treatment of strongly correlated systems. Starting with the basics of the microscopic theory of magnetism, one proceeds with relatively elementary arguments to such topics of current interest as the Mott transition, heavy fermions, and quantum magnetism. The basic approach is that magnetism is one of the manifestations of electron-electron interaction, and its treatment should be part of a general discussion of electron correlation effects.Though the text is primarily theoretical, a large number of illustrative examples are brought from the experimental literature. There are many problems, with detailed solutions.The book is based on the material of lectures given at the Diploma Course of the International Center for Theoretical Physics, Trieste, and later at the Technical University and the R. Eötvös University of Budapest, Hungary.

Creative Complex Systems

Creative Complex Systems PDF

Author: Kazuo Nishimura

Publisher: Springer Nature

Published: 2021-10-26

Total Pages: 427

ISBN-13: 9811644578

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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.

Modern Theory of Magnetism in Metals and Alloys

Modern Theory of Magnetism in Metals and Alloys PDF

Author: Yoshiro Kakehashi

Publisher: Springer Science & Business Media

Published: 2013-01-11

Total Pages: 344

ISBN-13: 3642334016

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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.