CONTRIBUTION TO MANY THEORETICAL PROBLEMS ABOUT RARE EARTHS MAGNETISM PDF Download

Author: Jean-Jacques Niez
Publisher:
ISBN:
Category :
Languages : en
Pages : 189

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Book Description
L'IMPORTANCE DU COUPLAGE SPIN-ORBITE DE LA BANDE 4F RESPONSABLE DU MAGNETISME ENTRAINE QUE LES PROPRIETES MAGNETIQUES SONT TRES SENSIBLES A LA SYMETRIE LOCALE DES SITES MAGNETIQUES ET FAIT APPARAITRE DES EFFETS ANISOTROPES. MISE EN EVIDENCE DE CES EFFETS DANS TROIS TYPES DE PROBLEMES: LES DEFAUTS, LES DOMAINES, LE DETAIL MICROSCOPIQUE DES INTERACTIONS. ETUDE DES PAROIS ETROITES DANS LES SUBSTANCES FERROMAGNETIQUES A FORTE ANISOTROPIE RELATIVE. ETUDE DE QUELQUES ASPECTS DU COMPORTEMENT MAGNETIQUE D'UN SYSTEME CUBIQUE DECRIT PAR UN HAMILTONIEN D'ECHANGE ANISOTROPE. DETERMINATION PAR ARGUMENTS DE SYMETRIE DES DIFFERENTES CONTRIBUTIONS AU CHAMP D'"AUTO-POLARISATION" OU AU NOYAU D'UN LANTHANIDE ET A LA POLARISATION DE LA BANDE DE CONDUCTION DANS LES COMPOSES CUBIQUES DE LANTHANIDES LNAL::(2)

Author: Jens Jensen
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 426

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Book Description
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.

Author: M Donath
Publisher: World Scientific
ISBN: 9814544663
Category : Science
Languages : en
Pages : 470

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Book Description
The interplay of magnetism and electronic correlations dominates the physical properties of many rare-earth elements and their compounds. The investigation of the mutual influence of the localized 4f electrons and itinerant band electrons represents a challenging task in theoretical as well as experimental physics. Research areas of current interest are the electronic structure as determined from calculations and spectroscopies, the magnetic properties in three- and low-dimensional systems, open questions concerning transport such as spin disorder resistivity, and the influence of structure and morphology.

Author: R. Elliott
Publisher: Springer Science & Business Media
ISBN: 1475756917
Category : Technology & Engineering
Languages : en
Pages : 430

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Book Description
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.

Author: D. Wagner
Publisher: Elsevier
ISBN: 1483156680
Category : Science
Languages : en
Pages : 295

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Book Description
Introduction to the Theory of Magnetism is an introductory text on the theory of magnetism. The discussions are organized around diamagnetism, paramagnetism, and ferromagnetism. The exchange interaction and the resulting many-particle problem for a system of atomic spins are also considered, and the properties of this system are examined in several approximations. This book is comprised of three chapters and begins with a review of the fundamental effects of diamagnetism, paying particular attention to the Bohr-van Leeuwen theorem, the Fermi gas, Landau levels, and cyclotron resonance. The diamagnetism of atoms and ions and of electrons is also described, and the magnetic moment of a free electron gas produced by the intrinsic magnetic moment of the electrons is calculated. The next chapter is devoted to the classical theory of paramagnetism and covers the paramagnetism of free electrons, free atoms (rare earths), and atoms in a crystal. Paramagnetic resonance and the Zeeman effect of free atoms are highlighted. The third and last chapter focuses on ferromagnetism and ferromagnetic resonance, together with the molecular-field approximation, spin waves, high temperatures, and the band model. This monograph will be a valuable resource for students of physics.

Author: A.K. Suri
Publisher: Routledge
ISBN: 1351448978
Category : Science
Languages : en
Pages : 272

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Book Description
The growth and development witnessed today in modern science, engineering, and technology owes a heavy debt to the rare, refractory, and reactive metals group, of which niobium is a member. Extractive Metallurgy of Niobium presents a vivid account of the metal through its comprehensive discussions of properties and applications, resources and resource processing, chemical processing and compound preparation, metal extraction, and refining and consolidation. Typical flow sheets adopted in some leading niobium-producing countries for the beneficiation of various niobium sources are presented, and various chemical processes for producing pure forms of niobium intermediates such as chloride, fluoride, and oxide are discussed. The book also explains how to liberate the metal from its intermediates and describes the physico-chemical principles involved. It is an excellent reference for chemical metallurgists, hydrometallurgists, extraction and process metallurgists, and minerals processors. It is also valuable to a wide variety of scientists, engineers, technologists, and students interested in the topic.

Author: R L White
Publisher: Elsevier
ISBN: 1483269116
Category : Science
Languages : en
Pages : 275

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Book Description
Magnetism and Magnetic Materials: 1965 Digest: A Survey of the Technical Literature of the Preceding Year focuses on the processes, methodologies, reactions, technologies, and advancements in magnetism and magnetic materials. The selection first offers information on general theoretical problems, including spin-wave dispersion, exchange integral, magnetic ordering, soluble models, magnetic phase transitions, and conduction electron spin polarization. The text then ponders on neutron diffraction, spin configurations, and magnetic transitions and properties of transition metals and their alloys. Topics include neutron scattering theory and equipment; spin configurations and magnetic transitions; magnetic behavior; rare earth alloys and compounds; and other alloys and compounds. The publication takes a look at the properties of magnetically dilute alloys and rare earth metals and their alloys. Discussions focus on rare earth intermetallic compounds, transition metals in noble metals, and other dilute alloys. The text then examines the technical properties of soft magnetic materials, magnetically hard materials, thin films, and nuclear magnetism. The selection is a valuable source of data for readers interested in magnetism and magnetic materials.

Author: Nguyen Dinh Noan
Publisher: Independently Published
ISBN: 9781799165644
Category : Science
Languages : en
Pages : 220

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Book Description
Hurry up and get YOUR copy NOW❗ Discovering Secrets about EARTH MAGNETISM: Problems With Electric Charges, On Earth, In Atmosphere, In Van Allen Belt And On The Moon❗ Dear Readers, I study and compile my research results in a book. My purpose is to offer my book for publishing in Singapore and distributing to the world. The book is sorted as Earth Basic Science; semi-empirical research, its title is "Problems With Electric Charges, On Earth, In Atmosphere, In Van Allen Belt And On The Moon." Since 70th years in Marine University, I did battle with the issue of Earth Magnetism, but tens of questions are left behind when I left that school. Such long time of more than 30-year period seems not enough for me to consider the problems of Earth Magnetism, but I do come back with Earth Science and study Earth Magnetism again. Should we begin with "the spinning & magnetism"? This question has been asked for long ago but known to the world since 1915 when Samual J.Barnet (an American scientist) introduced his invent: the Barnet effect. The effect is stated in general: any neutral object (no electric charge on it) spins to induce magnetism. That scientist, the author of his invent applied such theory to explain the origin of Earth Magnetism. He failed or is not accepted. We now begin again with Earth rotation and its magnetism; nonetheless we don't introduce a shock in science, but we do introduce a new view to Earth Magnetism: it spins with electric charges on it cum in the electric field of some others, that's how it is magnetized. Certainly we are at a large gap away from Samual J. Barnet. The gap is not just 102-year interim; it is a view to magnetism in general and Earth Magnetism in my research. The gap is presented in this book with several chapters in 200 pages. I am neither going to deny the settled theories about E.M nor to make the Geomagnetism up-side-down, but consider the E.M as one constituted by 2 major parts: - The "part I" for sea & land: This mainly comprises 2 compositions that induced by the charges at sea surface and land surface, they are both on Earth. The very special paradox is that "land charges versus sea surface charge in contributing to the E.M whilst they both are moving together with Earth's rotation." - The other-external inducers: is one that contributed by external magnetic inducers such as Van Allen belt, Moon and atmosphere. The simple principle governing this part is that the Earth is rotating in electric fields of many charges; that's how the Earth is magnetized. Meantime, in this part I point out that the Moon is charged and its charge induces magnetism to the Earth during orbiting around our planet in a cycle of 29.5 x 24 hrs. Like any other authors, I wish my book to be printed and sold. Unlike some other author, my book is my claim about my discovery. Thank you for your kind attention, Don't delay any more seconds, scroll back up, DOWNLOAD your copy NOW for only $2.99 and start the journey of mastering essential legal terms explained about EARTH MAGNETISM TODAY! Tags: earth magnetism, earths magnetic field, earth magnet, rare earth magnets, big earth magnets, rare earth magnets small, rare earth magnets large, n52 rare earth magnets, raw earth magnets, large earth magnet

Author: Uygun V. Valiev
Publisher: Scientific Research Publishing, Inc. USA
ISBN: 1618960547
Category : Science
Languages : en
Pages : 146

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Book Description
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.

Author: A.R. Jha
Publisher: CRC Press
ISBN: 1466564024
Category : Science
Languages : en
Pages : 378

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Book Description
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