Research On Rare Earth Metals And Compounds And Development Of Applications Based On Their Magnetic Properties

The report describes the technical acomplishments achieved during a one year research program on the magnetic and magnetoelastic properties of materials containing elements of the rare-earth series. A primary goal of this program was the development of highly efficient high-frequency ultrasonic transducers based on the extremely high magnetostriction found in most rare-earth materials. Work has been carried out on the propagation of elastic waves in holmium and terbium single crystals, and results have been obtained for the velocity and attenuation of such waves as functions of the temperature and the strength of an applied magnetic field. Single-crystal transducers of gadolinium and terbium have been constructed, and elastic-wave generation in these transducers has been observed, although only preliminary results have been attained. A new theory of magnetic and magnetoelastic effects in the rare earths has been developed, and it promises to shed new light on these phenomena. A facility for the growth of large single crystals of rare-earth materials has been constructed, making possible the study of a wide range of materials. (Author).

Recent studies indicate that China accounts for about 96 percent of the world’s supply of rare earth materials (REMs). With REMs becoming increasingly important for a growing number of high-tech applications, appropriate action must be taken to mitigate the effects of a shortage of critical REMs in defense systems and components. Bringing together information previously available only from disparate journal articles and databases, Rare Earth Materials: Properties and Applications describes the unique characteristics and applications of 17 REMs. It defines their chemical, electrical, thermal, and optical characteristics. Maintaining a focus on physical and chemical properties, it addresses the history and critical issues pertaining to mining and processing of REMs. In this book, Dr. A.R. Jha continues his distinguished track record of distilling complex theoretical physical concepts into an understandable technical framework that can be extended to practical applications across commercial and industrial frameworks. He summarizes the chemical, optical, electrical, thermal, magnetic, and spectroscopic properties of REMs best suited for next-generation commercial and military systems or equipment. Coverage includes extraction, recycling, refinement, visual inspection, identification of spectroscopic parameters, quality control, element separation based on specific application, pricing control, and environmental / geo-political considerations. Potential applications are identified with an emphasis on scientific instruments, nuclear resonance imaging equipment, MRI systems, magnetic couplers for uranium enrichment equipment, battery-electrodes, electric motors, electric generators, underwater sensors, and commercial and military sensors. The book describes unique applications of rare earth magnets in all-electric and hybrid electric cars and microwave components. It also considers the use of rare earth magnets in commercial and military systems where weight and size are the critical design requirements. Suitable for both students and design engineers involved in the development of high-technology components or systems, the book concludes by summarizing future applications in electro-optic systems and components, including infrared lasers, diode-pumped solid-state lasers operating at room temperatures, and other sophisticated military and commercial test equipment

A comparison of theory with experiment is made for rare-earth compounds with garnet structure and orthoaluminate whose optical, magnetic and magnetooptical features have been studied sufficiently well by now.

This book presents advances in the field of rare-earth (R) – transition metal (M) – boron compounds with extensive references. Since titanium and scandium do not form compounds with rare-earths, the Sc/Ti-M-B series are additionally presented. In each chapter the crystal structures, the complex physical properties as determined from neutron diffraction, magnetic measurements, resonance studies, transport properties and band structure calculations are critical analyzed. The models used in describing the experimental evidence are also presented. Tables with the main properties of the R-M-B compounds are given and representative data are illustrated in figures. In this way, the book provides state-of-the art knowledge and a valuable analysis of up-to-date results in the field. The technical applications, as permanent magnets, thermoelectric and magnetocaloric devices, hydrogen storage are also highlighted along with the authors insights into future directions in the field. The book is of interest for scientists involved in the development of the field as well as those working in the technical uses of rare-earth compounds.

New Frontiers in Rare Earth Science and Applications, Volume II documents the proceedings of the International Conference on Rare Earth Development and Applications held in Beijing on September 10-14, 1985. This compilation discusses quenching and sensitization of rare earth luminescence, magnetic properties of rare earth intermetallics, and microcapsulated rare earth-nickel hydride-forming materials. The effect of rare earth on the quality and properties of hot-rolled steel strips and role of yttrium in heavy section spheroidal graphite cast iron are also elaborated. This book likewise covers the application of scandium oxide in an electron emission material and study on the effect of rare earth elements on the yield of wheat. This publication is beneficial to researchers and scientists conducting work in the field of earth science.

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.

Edited by a highly regarded scientist and with contributions from sixteen international research groups, spanning Asia and North America, Rare Earth Coordination Chemistry: Fundamentals and Applications provides the first one-stop reference resource for important accomplishments in the area of rare earth. Consisting of two parts, Fundamentals and Applications, readers are armed with the systematic basic aspects of rare earth coordination chemistry and presented with the latest developments in the applications of rare earths. The systematic introduction of basic knowledge, application technology and the latest developments in the field, makes this ideal for readers across both introductory and specialist levels.

Progress in the Science and Technology of the Rare Earths, Volume 2 is a collection of papers that details the advancement in various areas of rare earth technology. The coverage of the text includes the practical applications and methods of preparation of rare earth materials. The selection also covers topics about the various properties of rare earths, such as the molecular field model of exchange coupling in rare earth materials; thermodynamic and magnetic properties of the rare earth chalcogenides and pnictides; and structural and solid state chemistry of pure rare earth oxides. The book will be of great use to individuals involved in the research and development of technologies that utilize rare earth materials.

Rare-earth intermetallics, also known as lanthanide elements, play an important role in the study of magnetic materials and the development of semi- and super-conducting materials. This handbook provides an up-to-date compilation of crystallographic, physical, and magnetic data on rare-earth intermetallic compounds. Over 20 different structure types are described in detail with an emphasis on how crystal structure can affect magnetic properties. Theoretical models for magnetic interactions are described as well as the impact of crystal electric fields on transport properties, magneto crystalline anistropy and hyperfine interactions. This book provides materials scientists, engineers and physicists with all the critical information needed to use rare-earth intermetallics effectively in the development of new materials.