Theory of Heavy Fermions and Valence Fluctuations


Book Description

This volume contains the proceedings of the Eighth Taniguchi Interna tional Symposium on the Theory of Condensed Matter, which was held at Shima Kanko Hotel in Shima, Japan, 10-13 April 1985. The topic of the Symposium was Valence Fluctuation and Heavy Fermion Systems, one of the most fundamental problems in present-day condensed matter physics. The dilute Kondo problem, which is one of the most typical and unique many-body problems in condensed matter physics, developed recently into the dense Kondo and the coherent Kondo lattice problems in the 4f elec tron systems. It is accepted now that a large degeneracy in f-electron systems makes this latter situation possible by enhancing the single-site Kondo state relative to the inter-site magnetic interactions. Now, anoma lous behavior in f-electron systems show rich variety and are called valence fluctuation phenomena as a whole. They have, however, a common fea ture. In the lowest temperature region, they show either heavy Fermion like character or a narrow gap formation at the Fermi energy. Discovery of superconductivity in the heavy Fermion systems is attracting more in terest. Anyway, the valence fluctuating states are thought to be of fun damental importance to bridge the gap between the localized magnetic states and the delocalized nownagnetic states.




Theoretical and Experimental Aspects of Valence Fluctuations and Heavy Fermions


Book Description

During the Koln meeting (August 28-31, 1984), Irdia was chosen as the venue for the next International Conference on Valence Fluctuations. lhis was in recognition ard appreciation of the work done, both experimental ard theoretical, by the Irdian scientists in this area during the last decade. We decided to hold this Conference in the month of January, 1987 at Bangalore. lhe subject of Valence Fluctuations has kept itself alive ard active as it has provided many shocks ard suprises particularly among the Ce- ard U-based intermetallies. lhe richness of many interesting physical phenomena occurring in mixed valent materials, the flexibility of modifying their physical properties (by alloying, for example) ard the possibility of synthesizing a wide variety of new such materials seem to be the key factors in this regard. Barely six months before this Conference, an International Conference on Anomalous Rare Earths and Actinides (ICAREA) had been held at Grenoble (July, 1986) which also focussed on mixed valence ard heavy fermion phenomena. In spite of this, the response to this' Conference was very enthusiastic and encouraging. Many interesting ard important results were presented at this Conference which have been included in this volume.




Theoretical and Experimental Aspects of Valence Fluctuations and Heavy Fermions


Book Description

During the Koln meeting (August 28-31, 1984), Irdia was chosen as the venue for the next International Conference on Valence Fluctuations. lhis was in recognition ard appreciation of the work done, both experimental ard theoretical, by the Irdian scientists in this area during the last decade. We decided to hold this Conference in the month of January, 1987 at Bangalore. lhe subject of Valence Fluctuations has kept itself alive ard active as it has provided many shocks ard suprises particularly among the Ce- ard U-based intermetallies. lhe richness of many interesting physical phenomena occurring in mixed valent materials, the flexibility of modifying their physical properties (by alloying, for example) ard the possibility of synthesizing a wide variety of new such materials seem to be the key factors in this regard. Barely six months before this Conference, an International Conference on Anomalous Rare Earths and Actinides (ICAREA) had been held at Grenoble (July, 1986) which also focussed on mixed valence ard heavy fermion phenomena. In spite of this, the response to this' Conference was very enthusiastic and encouraging. Many interesting ard important results were presented at this Conference which have been included in this volume.




Magnetism in Heavy Fermion Systems


Book Description

Magnetism in Heavy Fermion Systems is a review volume which covers an important subset of topics in the field of heavy fermion and non-Fermi liquid physics. It summarizes much of the experimental information in these areas, and includes an article which discusses theoretical interpretations of the complex magnetic behavior of heavy fermion systems. The topics covered include heavy fermion superconductivity, muon spin relaxation in small-moment heavy fermions, neutron scattering from heavy fermions, random localized magnetism in heavy fermions, and magnetism in Pr-containing cuprates. One feature of the book which should be helpful to graduate students and new workers in the field is the extensive references and a separate list of review articles.




Anomalous Rare Earths and Actinides


Book Description

Anomalous Rare Earths and Actinides: Valence Fluctuation and Heavy Fermions focuses on the characteristics, reactions, transformations, technologies, and processes involved in the study of anomalous rare earths and actinides. The selection first offers information on lanthanides and actinides and electronic structures in cerium monopnictides. Topics include rare earth metals with fluctuating valencies, 'normal' rare earth metals, and band calculation and Fermi surface. The text then elaborates on neutron scattering studies of anomalous rare earth compounds, including magnetic neutron scattering measurements, stability and localization of magnetic moments, and condensed state. The manuscript examines the transport properties of cerium monochalcogenides and pressure-volume relationships of cerium monochalcogenides and monopnictides. The text also ponders on the theory of anisotropic magnetic behavior in hybridizing actinide systems; band hybridization effects on indirect magnetic coupling of localized moments; and neutron scattering from transuranium materials. The selection is a dependable reference for readers interested in the research on anomalous rare earths and actinides.




Heavy-Fermion Systems


Book Description

The book on Heavy-Fermion Systems is a part of the Book series "Handbook of Metal Physics", each volume of which is written to facilitate the research of Ph.D. students, faculty and other researchers in a specific area. The Heavy-Fermions (sometimes known as Heavy-Electrons) is a loosely defined collection of intermetallic compounds containing rare-earth (mostly Ce) or actinide (mostly U) elements. These unusual names were given due to the large effective mass (100-1,000 times greater than the mass of a free electron) below a critical temperature. They have a variety of ground states including superconducting, antiferromagnetic, paramagnetic or semiconducting. Some display unusual magnetic properties such as magnetic quantum critical point and metamagnetism. This book is essentially a summary as well as a critical review of the theoretical and experimental work done on Heavy Fermions.· Extensive research references.· Comprehensive review of a very rapidly growing number of theories.· Summary of all important experiments.· Comparison with other highly correlated systems such as High-Tc Superconductors.· Possible Technological applications.




Physics Of Heavy Fermions: Heavy Fermions And Strongly Correlated Electrons Systems


Book Description

A large variety of materials prove to be fascinating in solid state and condensed matter physics. New materials create new physics, which is spearheaded by the international experimental expert, Prof Yoshichika Onuki. Among them, the f electrons of rare earth and actinide compounds typically exhibit a variety of characteristic properties, including spin and charge orderings, spin and valence fluctuations, heavy fermions, and anisotropic superconductivity. These are mainly manifestations of better competitive phenomena between the RKKY interaction and the Kondo effect. The present text is written so as to understand these phenomena and the research they prompt. For example, superconductivity was once regarded as one of the more well-understood many-body problems. However, it is, in fact, still an exciting phenomenon in new materials. Additionally, magnetism and superconductivity interplay strongly in heavy fermion superconductors. The understanding of anisotropic superconductivity and magnetism is a challenging problem in solid state and condensed matter physics. This book will tackle all these topics and more.




Rare-Earths and Actinides in High Energy Spectroscopy


Book Description

This unique monograph covers recent theoretical and experimental results on the complex character of f electrons in materials containing lanthanides (rare earths) or actinides, such as alpha-cerium and delta-plutonium. It answers the urgent need for a general presentation of the body of experimental and theoretical results presently available in this challenging domain. Some of the fast developing applications of lanthanide and actinide materials are mentioned. Materials containing atoms with an open f shell have electronic and crystalline properties that are controlled by the localized or delocalized character of the f electrons. This book gives a theoretical discussion of the various spectroscopic methods that shed light on the character of the f electrons and on the connection between their localization and the properties of these materials. Part 1 covers the characteristics of the f electrons in atoms and solids and includes a discussion of the properties of lanthanides and actinides in connection with the f electrons. Part 2 describes the various spectroscopic methods that are used to establish the electronic distributions and energies of the states. Examples involve the determination of f electron distributions by high energy spectroscopy methods with separate treatment of the valence and core electrons. Part 3 concentrates on the theoretical treatment of electronic transitions involving f electrons and simulations of the lanthanide spectra, including comparison with the available experimental data. Part 4 discusses the localized or delocalized character of the f electrons in actinides and their compounds, including comparison (analogies & differences) between the 4f and 5f electron materials. This monograph should be of great value for researchers, academics and engineers working in the fields of high energy spectroscopy, electronic and nuclear science and technology, as well as materials involving rare earths and radio-elements.




Materials Science in Static High Magnetic Fields


Book Description

Presents the most comprehensive review of the influence of highly intense magnetic fields on materials of various classes.