Spin Fluctuation Theory of Itinerant Electron Magnetism

Spin Fluctuation Theory of Itinerant Electron Magnetism

Author: Yoshinori Takahashi

Publisher: Springer

ISBN: 3642366678

Category: Science

Page: 181

View: 790

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

Author: Toru Moriya

Publisher: Springer Science & Business Media

ISBN: 9783642824999

Category: Technology & Engineering

Page: 242

View: 494

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.

Spin Fluctuation Theory of Itinerant Electron Magnetism

Spin Fluctuation Theory of Itinerant Electron Magnetism

Author: Yoshinori Takahashi

Publisher: Springer

ISBN: 9783642366666

Category: Science

Page: 181

View: 299

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.

Itinerant Electron Magnetism: Fluctuation Effects

Itinerant Electron Magnetism: Fluctuation Effects

Author: Dieter Wagner

Publisher: Springer Science & Business Media

ISBN: 9789401150804

Category: Science

Page: 460

View: 553

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.

Dynamic Spin-Fluctuation Theory of Metallic Magnetism

Dynamic Spin-Fluctuation Theory of Metallic Magnetism

Author: Nikolai B. Melnikov

Publisher: Springer

ISBN: 9783319929743

Category: Science

Page: 287

View: 729

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.

Theory of Itinerant Electron Magnetism

Theory of Itinerant Electron Magnetism

Author: Jürgen Kübler

Publisher: Oxford University Press

ISBN: 9780191565427

Category: Science

Page: 494

View: 360

This book, in the broadest sense, is an application of quantum mechanics and statistical mechanics to the field of magnetism. Under certain well described circumstances, an immensely large number of electrons moving in the solid state of matter will collectively produce permanent magnetism. Permanent magnets are of fundamental interest, and magnetic materials are also 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 local density functional approximation. The emphasis is on realistic magnets, for which the equations describing the many electron problem can only be solved by using computers. The great, recent and continuing improvements of computers are, to a large extent, responsible for the progress in the field. Along with a detailed introduction to the density functional theory, this book presents representative computational methods and provides the reader with a complete computer programme for the determination of the electronic structure of a magnet on a PC. A large part of the book is devoted to a detailed treatment of the connections between electronic properties and magnetism, and how they differ in the various known magnetic systems. Current trends are exposed and explained for a large class of alloys and compounds. The modern field of artificially layered systems - known as multilayers - and their industrial applications are dealt with in detail. Finally, an attempt is made to relate the rich thermodynamic properties of magnets to the ab initio results originating from the electronic structure.

Concise Encyclopedia of Magnetic and Superconducting Materials

Concise Encyclopedia of Magnetic and Superconducting Materials

Author: K.H.J. Buschow

Publisher: Elsevier

ISBN: 0080457657

Category: Technology & Engineering

Page: 1360

View: 507

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.

The Kyoto Manifesto for Global Economics

The Kyoto Manifesto for Global Economics

Author: Stomu Yamash’ta

Publisher: Springer

ISBN: 9789811064784

Category: Business & Economics

Page: 550

View: 809

This book confronts the failings of current global economics to deliver the equity, sustainability and community empowerment which humanity now needs to handle a troubled future. The volume proposes an economy built from our society, not the other way around. The Kyoto Manifesto was built, layer by layer, over a period of 4 years, based on broad-ranging international symposia held in Kyoto between 2014 and 2017, hosted by the Center for the Creative Economy, Doshisha University. Not stopping at theory and untested ideas however, the Manifesto proposes practical action that will make a difference, including in the problematic technological and ecological context of humanity’s immediate and long-term future. The book is unique and innovative for it moves adventurously across very broad territory. The Manifesto draws from world philosophic arguments, including, specifically, a critique of “liberalism”, further, exploring sociology, cultural anthropology, politics, primatology and early humanity, even quantum physics. Argument is set within mainstream post-1972 economics and political economics as well as direct practical experience working to empower disadvantaged communities through the United Nations. Most importantly, the book’s analysis is deeply informed by the practice of searching for what is “sacred”, the ultimate essence of our humanity, what we can be as a human race—empowered, fulfilled individuals, deeply sharing and caring for each other across our separate cultures and lives. Stomu Yamash’ta’s On Zen performances, set the context for the Symposia, bringing different religions and cultures together across their dividing boundaries into a coherent search for peace and harmony through sacred music. Informed by alternate cultural paradigms for economics, the book probes deeply into philosophies and practices that already exist within Eastern and Western societies, and offer lessons for our future. The result is an economics that stresses harmony with nature, and balance in social relations. It places an emphasis on community—human sharing and trust—as a platform for our future, not separate from the global economy but integrated into its very foundations. This is a book for all who care: a plan for our sustainable future built from the best of what our humanity is and can offer.

Theory of Itinerant Electron Magnetism

Theory of Itinerant Electron Magnetism

Author: Jürgen Kübler

Publisher: Oxford University Press

ISBN: 9780198500285

Category: Science

Page: 427

View: 565

This book, in the broadest sense, is an application of quantum mechanics and statistical mechanics to the field o 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.