Colossal Magnetoresistance Charge Ordering And Related Properties Of Manganese Oxides

Metal oxides constitute one of the most amazing classes of materials with a wide range of properties. They exhibit a variety of phenomena, such as ferroelectricity, ferromagnetism and superconductivity. A new aspect of metal oxides -- colossal magnetoresistance exhibited by certain manganese oxides, in particular rare earth manganates of perovskite structure -- has received much attention in the last four years. Some of these oxides show 100% magnetoresistance and have much potential for technological applications. Previously this phenomenon was found only in layered and granular metallic materials. Studies of colossal magnetoresistance have led to the discovery of many other new phenomena and properties such as charge ordering and orbital ordering. In view of the importance of colossal magnetoresistance, charge ordering and related phenomena exhibited by oxides to the physics and chemistry of solid materials, it is necessary and timely to have a book dealing with these topics. This book begins with a review of the subject followed by contributions from a number of experts which cover the present status of the subject.

The features and mechanism of Colossal Magnetoresistance, or CMR, in manganese oxides as well as device physics are highlighted in this book, with a focus on tunneling MR for some artificial structures. Underlying new science, such as tunable electron-lattice interaction in a metal and roles of orbital degrees of freedom in producing an unconventio

This invaluable book comprises assorted recent papers of Professor C N R Rao, a well-known chemist. It presents current trends in materials chemistry and physics, offering in-depth information to young researchers and pleasant reading to experts. Advances in Chemistry brings out the single-minded dedication of Professor Rao to the promotion of science. Contents:Highlights of Materials ChemistryTransition Metal Oxides (Including Cuprate Superconductors)Colossal Magnetoresistance, Charge Ordering and Related Aspects of Rare Earth ManganatesNanoparticlesNanotubes and NanowiresMolecular SolidsPorous SolidsOpen Framework Materials Readership: Students and researchers in industry and academia. Keywords:Metal Oxides;Magnetoresistance;Nanoparticles;Molecular Solids;Porous Solids

The study of the spontaneous formation of nanostructures in single crystals of several compounds is now a major area of research in strongly correlated electrons. These structures appear to originate in the competition of phases. The book addresses nanoscale phase separation, focusing on the manganese oxides known as manganites that have the colossal magnetoresistance (CMR) effect of potential relevance for device applications. It is argued that the nanostructures are at the heart of the CMR phenomenon. The book contains updated information on manganite research directed to experts, both theorists and experimentalists. However, graduate students or postdocs will find considerable introductory material, including elements of computational physics.

The physics of transition metal oxides has become a central topic of interest to condensed-matter scientists ever since high temperature superconductivity was discovered in hole-doped cuprates with perovskite-like structures. Although the renewed interest in hole-doped perovskite manganites following the discovery of their colossal magnetoresistance (CMR) properties, began in 1993 about a decade after the discovery of high temperature superconductivity, their first investigation started as early as 1950 and basic theoretical ideas were developed during 1951-1960. Experience in sample preparation and characterization, and in growth of single crystals and epitaxial thin films, gained during the research on high temperature superconductors, and the development of theoretical tools, were very efficiently used in research on CMR manganites. In early nineties it appeared to many condensed matter physicists that although the problem of high temperature superconductivity is a difficult one to solve, a quantitative understanding of CMR phenomena might be well within reach. This book is intended to be an account of the latest developments in the phys ics of CMR manganites. When I planned this book back in 2000, I thought that research on the physics of CMR manganites would be more or less consolidated by the time this would be published. I was obviously very optimistic indeed. We are now in 2003 and we still do not have a quantitative understanding of the central CMR effect. Meanwhile the field has expanded. It is still a very active field of research on both the experimental and theoretical fronts.

Perovskites are among the most famous materials due to their exceptional properties: they present nearly all existing types of interesting properties, in particular as ferroics or multiferroics, they may be insulators, (super)conductors, or semiconductors, magnetoresistant, they are used in numerous devices, they present hundreds of variants and different crystalline phases and phase transitions, and recently appeared as probably the most promising materials for photovoltaics. With a crystal structure characterized by octahedra that share their corners, these materials belong to the wider category of « Framework Structure (FWS) materials » the structure of which is based on units (octahedra, tetrahedra, …) that share some of their corners (or edges) with their neighbours. This particular feature of FWS materials confers to them unique properties. This review volume is constituted of 26 chapters on different aspects, and is divided in two parts, « Fundamental aspects and general properties », and « Elaborated materials and applied properties ». Its main purpose is to attempt to identify the properties common to all members of the vast family of FWS materials, and understand their differences. Besides perovskites, derived compounds as 2D perovskites, Dion-Jacobson, Ruddlesden-Popper, Aurivillius, tungsten-bronzes, and others, are presented, and their preparation and/or properties as single crystals, ceramics, thin films, multilayers, nanomaterials, nanofibers, nanorods, etc, are discussed. We focus on new trends and important recent developments by leaving somewhat aside more classical aspects which can be easily found in older textbooks or review articles. Among most recent applications, this volume focuses on applications related with interactions with other molecules, on photovoltaics, and on memories, with a special attention to perovskite solar cells that have certainly attracted the most attention of researchers in recent years, opening extremely promising routes in photovoltaics. In conclusion, this book presents a collection of texts elucidating various aspects of the relation between structural organization (including dynamical aspects) and singular properties of framework crystals; it proposes a reasonable balance between experimental and theoretical results, and between fundamental aspects and applied properties. This volume can be approached on several levels (each chapter initially assumes that the reader is not a specialist in the subject, and is presented in a pedagogical way) : it is accessible to master or doctoral students, as well as to researchers who want to have informations on recent developments, who will find excellent detailed introductions up to hotsubjects. It may also be used by undergraduate students who should approach given subjects. The volume contains 800 pages written by about 70 authors from different countries, it has an index, and is completed by numerous figures to illustrate the text.

Magnetic perovskite with multi functional properties (magneto-resistive, magneto-dielectric, multiferroics, spintronics, etc.) have attracted increasing attention due to their possible applications towards storage materials and intriguing fundamental Physics. Despite the numerous investigations on multi functional materials in the past few years, a very few magnetic perovskites have been known to realize as ferromagnetic-insulators. In perovskites centred transition metal oxides strong interplay between lattice, charge, spin and/or orbital degrees of freedom provide a fantastic playground to tune their physical properties. The main purpose of this book is to introduce the phenomenon and physics of complex magnetism (phase separation, spin glass, frustrations, etc.) in perovskite manganites and cobaltites via an experimental approach. The book is organized into four chapters; Chap. 1 gives a brief introduction of various interesting phenomena in magnetic perovskites. Chapter 2 describes the results of the investigations on electronic phase separation and glassy ferromagnetism of the hole-doped perovskite manganites and cobaltites. Ordered and disordered effects and related aspects in hole-doped perovskite cobaltites are described in Chap. 3. Finally, in Chap. 4 the bismuth based magnetic perovskite is discussed.