Spin Fluctuations in Itinerant Electron Magnetism

Spin Fluctuations in Itinerant Electron Magnetism

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.


Interacting Electrons and Quantum Magnetism

Interacting Electrons and Quantum Magnetism

Author: Assa Auerbach

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 249

ISBN-13: 1461208696

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In the excitement and rapid pace of developments, writing pedagogical texts has low priority for most researchers. However, in transforming my lecture l notes into this book, I found a personal benefit: the organization of what I understand in a (hopefully simple) logical sequence. Very little in this text is my original contribution. Most of the knowledge was collected from the research literature. Some was acquired by conversations with colleagues; a kind of physics oral tradition passed between disciples of a similar faith. For many years, diagramatic perturbation theory has been the major theoretical tool for treating interactions in metals, semiconductors, itiner ant magnets, and superconductors. It is in essence a weak coupling expan sion about free quasiparticles. Many experimental discoveries during the last decade, including heavy fermions, fractional quantum Hall effect, high temperature superconductivity, and quantum spin chains, are not readily accessible from the weak coupling point of view. Therefore, recent years have seen vigorous development of alternative, nonperturbative tools for handling strong electron-electron interactions. I concentrate on two basic paradigms of strongly interacting (or con strained) quantum systems: the Hubbard model and the Heisenberg model. These models are vehicles for fundamental concepts, such as effective Ha miltonians, variational ground states, spontaneous symmetry breaking, and quantum disorder. In addition, they are used as test grounds for various nonperturbative approximation schemes that have found applications in diverse areas of theoretical physics.


Pi Electron Magnetism

Pi Electron Magnetism

Author: D. Arcon

Publisher: Springer Science & Business Media

Published: 2001-08-28

Total Pages: 218

ISBN-13: 3540416803

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Celebrating Volume 100: Thirty years ago Springer-Verlag together with a distinguished Board of Editors started the series Structure and Bonding. Initially the series was set up to publish reviews from different fields of modern inorganic chemistry, chemical physics and biochemistry, where the general subject of chemical bonding involves a metal and a small number of associated atoms. Three years ago the aims of the series was refined to span the entire periodic table and address structure and bonding issues wherever they may be relevant. Not only the traditional areas of chemical bonding will be dealt with but also nanostructres, molecular electronics, supramolecular structure, surfaces and clusters. With these aims in mind it is noteworthy that Volume 100 effectively reinforces and illustrates these ideals and is titled Pi-Electron Magnetism from Molecules to Magnetic Materials.


Crystalline Electric Field Effects in f-Electron Magnetism

Crystalline Electric Field Effects in f-Electron Magnetism

Author: Robert Guertin

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 571

ISBN-13: 1468486462

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The present conference, the fourth successive on this subject, was organized to commemorate the 75th birthday of Professor Wtodzimierz Trzebiatowski, one of the pioneers in the field of f-electron materials structure, particularly in the magnetism of actinides. This volume contains 64 papers presented at the conference held in Wroctaw, Poland, September 22-25, 1981. Twenty-one were invited talks. About 100 participants from 13 countries attended the meeting during four days of lecture presentation (note these two numbers have been constant for the last two conferences). The conference consisted of sessions devoted to the investigation of crystalline electric fields and structural effects by spectroscopic techniques, neutron diffraction, magnetic, thermodynamic and electrical measurements all over broad temperature, magnetic field and pressure ranges. Materials investigated included rare earth intermetallics, hydrides, diluted systems and actinides, and among them some exhibited singlet ground state behavior. The experimental results were supplemented by theory. It is our pleasure to mention those persons who helped us make the conference successful. The International Advisory Com mittee included W.J.L. Buyers, B.R. Cooper, J.E. Crow, P. Fulde, A. Furrer, T. Kasuya, L. Kowalewski, G.R. Lander, R. Lemaire and D. Wohlleben. We thank them for valuable suggestions concerning invited speakers. We also wish to thank the co-workers of the In stitute for Low Temperature and Structure Research of the Polish Academy of Sciences in Wroclaw, especially A. Baran, M. Grzebyk, K.


Spin Fluctuation Theory of Itinerant Electron Magnetism

Spin Fluctuation Theory of Itinerant Electron Magnetism

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.


Theory of Itinerant Electron Magnetism

Theory of Itinerant Electron Magnetism

Author: Jürgen Kübler

Publisher: Oxford University Press

Published: 2017-03-23

Total Pages: 494

ISBN-13: 0191565423

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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.


Itinerant Electron Magnetism: Fluctuation Effects

Itinerant Electron Magnetism: Fluctuation Effects

Author: Dieter Wagner

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 455

ISBN-13: 940115080X

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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.


Physics of Magnetism and Magnetic Materials

Physics of Magnetism and Magnetic Materials

Author: K.H.J Buschow

Publisher: Springer Science & Business Media

Published: 2007-05-08

Total Pages: 175

ISBN-13: 0306484080

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In this book, the fundamentals of magnetism are treated, starting at an introductory level. The origin of magnetic moments, the response to an applied magnetic field, and the various interactions giving rise to different types of magnetic ordering in solids are presented and many examples are given. Crystalline-electric-field effects are treated at a level that is sufficient to provide the basic knowledge necessary in understanding the properties of materials in which these effects play a role. Itinerant-electron magnetism is presented on a similar basis. Particular attention has been given to magnetocrystalline magnetic anisotropy and the magnetocaloric effect. Also, the usual techniques for magnetic measurements are presented. About half of the book is devoted to magnetic materials and the properties that make them suitable for numerous applications. The state of the art is presented of permanent magnets, high-density recording materials, soft-magnetic materials, Invar alloys and magnetostrictive materials. Many references are given.


Magnetic Atoms and Molecules

Magnetic Atoms and Molecules

Author: William Weltner

Publisher: Courier Corporation

Published: 1989-01-01

Total Pages: 460

ISBN-13: 9780486661407

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This comprehensive graduate-level text by a leading researcher in atomic and molecular spectroscopy explores the electron-spin-resonance theory of randomly oriented molecules. "I recommend it highly." ? American Scientist. 119 illustrations.