Magnetic Interactions In Rare Earth Borides

Rare-earth borides have attracted continuous interest for more than half a century both from the point of view of fundamental condensed matter physics and for practical applications in various fields of engineering. They demonstrate a wealth of unusual electronic and magnetic properties that have been closely investigated in recent decades using advanced spectroscopies and state-of-the-art physical characterization methods. Authored by leading experts in the field, this book features a comprehensive collection of reviews offering a cutting-edge summary of the research on rare-earth borides from various viewpoints. It includes chapters on the growth and characterization of single-crystal and thin-film samples, detailed description of their lattice structure and dynamics, electronic and magnetic properties in the bulk and at the surface, low-temperature ordering phenomena, and theoretical and experimental description of the unusual spectroscopic properties from the perspective of modern x-ray and neutron scattering, Raman spectroscopy, and electron spin resonance. The book will appeal to anyone interested in the physics and chemistry of solids and low-temperature physics, especially to researchers and postgraduate students who study magnetic and electronic properties of rare-earth compounds.

The aim of this work is to present a unified account of a limited area of rare-earth magnetism, the magnetic structures and excitations which reflect the nature of the fundamental magnetic interactions and determine many of the characteristic properties of metals.

This monograph presents a unified and coherent account of an important, focused area of rare-earth magnetism -- magnetic structures and excitations -- which both reflects the nature of the fundamental magnetic interactions and determines many of the characteristic properties of metals. The authors concentrate on the essential principles and their applications to typical examples, generally restricting the discussion to the pure elements and considering alloys and compounds only when they are instructive in illuminating particular topics. Both authors have been involved for some time in the effort that has been made in Denmark to study, both theoretically and experimentally, the magnetic structures and especially the excitations in the rare earths. This account of the subject represents the result of their experience, and it has been written in the hope that it will be useful not only to those who have a special interest in rare-earth magnetism, but also to a wider audience of physicists and condensed matter scientists interested in the techniques and achievements of modern research in magnetism.

The rare earths have a unique place among the elements. Although very much alike chemically and in most phy~ical properties they each have very different and striking magnetic properties. The reason, of course, lies in their 4f electrons which determine the magnetic properties but have little effect on other chemical and physical behaviour. Although they are not rare, some indeed are among the more common heavy elements in the earth's crust, the difficulty of separation has meant that their intricate magnetic properties have only recently been unravelled. Now, however, the general pattern of their magnetism is well charted and the underlying theory is well understood. Both are thoroughly summarised in this book. It provides an excellent example of the kind of extensive synthesis which is possible with modem solid state physics. it represents only a high plateau in the ascent to complete understanding. But It will become clear to the reader that while the overall position is satisfactory there are many details still to be elucidated experimentally and much to be done theoretically before all the underlying forces are identified and estimated from a priori calculations. It is hoped that the book will provide a useful stimulus in this direction. It should also be of use to those who are interested in related disciplines, for example the rare earth compounds, or the transition metals. In addition rare earths promise to be important technologically as alloy constituents.

V. I. MATKOVICH During the meeting of the International Symposium on Boron held in October, 1972 in Tbilisi, U.S.S.R., the idea was proposed to assemble a review of boron and refractory borides by the specialists present. The advantages of such a work were immediately apparent. Such diverse applications of borides as in protective armor, nuclear reactors, coat ings, reinforcement, etc. can hardly all be presented in sufficient detail by a single author. On the other hand it was also recognized that with so much specialization, some areas of interest may not be covered. Within the last decade or two a number of areas have been developed in which the use of refractory borides is growing and improvements are being actively explored. Thus, a number of borides have considerable potential as reinforcing material for plastics or light metals, though only boron fibers have been firmly established up to the present. Ap plication of flakes and films for two-dimensional reinforcement appears attractive, although the high cost of materials and development repre sents a considerable barrier. A number of borides have been used to manufacture lightweight protec tive armor. In this area relatively fast changes seem to be taking place as improvements in performance and weight are made. Boron carbide has found considerable use in this application and new developments exploit the light weight of beryllium borides.

Rare Earth Intermetallics provides an account of the magnetic characteristics of rare earth intermetallics. This book discusses bulk magnetic characteristics, such as temperature dependence of susceptibility, saturation magnetization, nature of the cooperative magnetic phase, low temperature specific heats, and related thermal properties. Other topics include the magnetic interactions, crystal field interaction by the operator equivalent method, and rare earth-nontransition metal systems. The miscellaneous IVA compounds, rare earth substitution, variation in the iron moment, and compounds with 4d and 5d transition metals are also elaborated in this text. This publication is recommended for students and researchers interested in rare earth intermetallics.

Lanthanides are of great importance for the electronic industries, this new book (from the EIBC Book Series) provides a comprehensive coverage of the basic chemistry, particularly inorganic chemistry, of the lanthanoid elements, those having a 4f shell of electrons. A chapter is describing the similarity of the Group 3 elements, Sc, Y, La, the group from which the lanthanoids originate and the group 13 elements, particularly aluminum, having similar properties. Inclusion of the group 3 and 13 elements demonstrates how the lanthanoid elements relate to other, more common, elements in the Periodic Table. Beginning chapters describe the occurrence and mineralogy of the elements, with a focus on structural features observed in compounds described in later chapters. The majority of the chapters is organized by the oxidation state of the elements, Ln(0), Ln(II), Ln(III), and Ln(IV). Within this organization the chapters are further distinguished by type of compound, inorganic (oxides and hydroxides, aqueous speciation, halides, alkoxides, amides and thiolates, and chelates) and organometallic. Concluding chapters deal with diverse and critically important applications of the lanthanoids in electronic and magnetic materials, and medical imaging.