Download or read book Investigation of Structural and Magnetic Properties of Perovskite Type Oxides Containing 5d Ions written by Jie Xiong and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this thesis work is to explore the exotic magnetism in perovskite type oxide materials containing 5d transition metal. Strong spin orbit coupling and extended 5d orbitals lay the foundation of unique orbital and spin interactions between 5d ions. Understanding the physics of 5d ions is not only of fundamental interests, but important in the search for new phases of matter such as topological insulators, Weyl semimetals and quantum spin liquids. Chapter 2 and 3 discuss the magnetic behavior of 5d1 and 5d2 ions on a face-centered cubic lattice embedded in the double perovskite structure. The crystal structure, transport and magnetic properties of double perovskites Ba2BReO6 (B=Cd, Zn, Sc, In, Lu, La), Sr2LuReO6 and Ca2ScReO6 are characterized by X-ray diffraction, neutron diffraction, dc electric conductivity, dc magnetometry and heat capacity. Ferromagnetic ground states are prevalent in 5d1 systems. Orbital degree of freedom dominates the magnetic behavior over a wide temperature range before the magnetic ordering, resulting in changing effective moments with temperature and artificial negative Weiss constants. The ground state is a delicate balance sensitive to factors such as spin orbit coupling, metal-oxygen covalency, and subtle structural details. On the other hand, 5d2 systems are dominated by antiferromagnetic ground states. Filling d orbitals on the diamagnetic ion tends to destroy long range magnetic ordering in compounds with cubic symmetry. Strong distortion of the octahedral environment of 5d2 ions can result in ionic singlet states, which is not possible in 5d1 systems. Chapter 4 investigates the superexchange coupling between 5d ions and 3d ions in ordered double perovskites Sr2-xCaxCoOsO6. The crystal structures and magnetic properties are characterized using X-ray diffraction, neutron diffraction and magnetometry. Independent magnetic ordering of Co and Os sublattices are found in Sr-heavy compounds with less structural distortions, stabilized by Co-Co interactions (Co-O-O-Co and Co-O-Os-O-Co superexchange coupling) and Os-Os interactions (Os-O-O-Os and Os-O-Co-O-Os superexchange coupling), respectively. The Os-Os interactions are more sensitive to structural distortions than the Co-Co interactions. As a result, magnetic ordering of the Os sublattice disappear at lower Ca doping level than that of the Co sublattice. The strength of Co-Os superexchange coupling increases as the structure gets more distorted, resulting in ferrimagnetic ordering between Co and Os sublattices on the Ca-heavy compound. Complex glassy behavior is present in a wide compositional range in between due to the presence of competing magnetic interactions.

Download or read book Magnetic Perovskites written by Asish K Kundu and published by Springer. This book was released on 2016-02-11 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book An Investigation of the Structure and Properties of 4d Transition Metal Perovskite Oxides written by Harriet A. Hopper and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Perovskite Oxides written by Gibin George and published by CRC Press. This book was released on 2020-10-06 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook entitled Fundamentals of Perovskite Oxides: Synthesis, Structure, Properties and Applications summarizes the structure, synthesis routes, and potential applications of perovskite oxide materials. Since these perovskite-type ceramic materials offer opportunities in a wide range of fields of science and engineering, the chapters are broadly organized into four sections of perovskite-type oxide materials and technology. Covers recent developments in perovskite oxides Serves as a quick reference of perovskite oxides information Describes novel synthesis routes for nanostructured perovskites Discusses comprehensive details for various crystal structures, synthesis methods, properties, and applications Applies to academic education, scientific research, and industrial R&D for materials research in real-world applications like bioengineering, catalysis, energy conversion, energy storage, environmental engineering, and data storage and sensing This book serves as a handy and practical guideline suitable for students, engineers, and researchers working with advanced ceramic materials.

Download or read book Investigating the Relationship Between Structure and Magnetic Ground States of 5d Double Perovskites written by Phuong Minh Tran and published by . This book was released on 2020 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this dissertation is to investigate the relationship between structure and magnetic properties of 5d double perovskites and double perovskite derivative structures through different chemical substitution. Because of high spin-orbit coupling, high interorbital repulsion, and the extended nature of the 5d orbitals, how the spin, orbital, and lattice degree of freedom couple in order to stabilize the magnetic ground state is not well understood. The aim of this dissertation is to perturb the crystal lattice with chemical pressure or charge defects and determine the sensitivity of the magnetic properties to these changes. Chapter 2 discusses the effect of distortions of the magnetic cation environment on the magnetic ground state of 5d1 double perovskites Sr2ZnReO6, Sr2LiOsO6, and Sr2NaOsO6. Chapter 3 discusses the effect of charge doping on the 5d1 magnetic ground state in the solid solution system Ba2NaxCa1-xOsO6. Chapter 4 is the exploration of the Ba2Sr2-xNiOsO6 in order to investigate the unusual magnetic ground states observed in double perovskites containing Ni2+ and Os6+.

Download or read book Properties and Applications of Perovskite Type Oxides written by L.G. Tejuca and published by CRC Press. This book was released on 2000-10-17 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference offers an overview of the bulk and surface properties of perovskite-like structures, and provides the latest discussions on the applications of these materials and processes. It also introduces ceramic methods for the processing of perovskite-derived high Tc cuprates.;Examining every available procedure for synthesizing high-surface-area perovskite oxides, this book: delineates processing techniques for preparing perovskite-derived high-critical-temperature superconductors; illustrates the relevance of physiochemical methods to investigate bulk and surface structures of perovskite compounds; explicates the importance of surface composition in the context of catalytic behaviour; summarizes methods of changing stoichiometry; shows how to design perovskite oxides for a given purpose; reviews key solid-state properties; and presents the major applications.

Download or read book Perovskite Metal Oxides written by Srikanta Moharana and published by Elsevier. This book was released on 2023-05-30 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perovskite Metal Oxides: Synthesis, Properties and Applications provides an overview on the topic, including the synthesis of various types of perovskites, their properties, characterization and application. The book reviews the applications of this category of materials for photovoltaics, electronics, biomedical, fuel cell, photocatalyst, sensor, energy storage and catalysis, along with processing techniques of perovskite metal oxides with a focus on low-cost and high-efficiency methods, including various properties and probable applications in academia and industry. Other sections discuss strategies to improve the functionality of perovskite metal oxide materials, including chemical methods and controlling the size, shape and structure of the materials. Finally, applications of perovskite metal oxides in energy conversion and storage, sensing and electronics are covered. Provides an overview of perovskite metal oxides, with an emphasis on synthesis, fabrication and characterization methods Discusses strategies to improve the functionality of perovskite metal oxide materials, including chemical methods and controlling the size, shape and structure of the materials Reviews applications of perovskite metal oxides in energy conversion and storage, sensing and electronics

Download or read book Perovskites and Related Mixed Oxides written by Pascal Granger and published by John Wiley & Sons. This book was released on 2016-02-23 with total page 1050 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive handbook and ready reference details all the main achievements in the field of perovskite-based and related mixed-oxide materials. The authors discuss, in an unbiased manner, the potentials as well as the challenges related to their use, thus offering new perspectives for research and development on both an academic and industrial level. The first volume begins by summarizing the different synthesis routes from molten salts at high temperatures to colloidal crystal template methods, before going on to focus on the physical properties of the resulting materials and their related applications in the fields of electronics, energy harvesting, and storage as well as electromechanics and superconductivity. The second volume is dedicated to the catalytic applications of perovskites and related mixed oxides, including, but not limited to total oxidation of hydrocarbons, dry reforming of methane and denitrogenation. The concluding section deals with the development of chemical reactors and novel perovskite-based applications, such as fuel cells and high-performance ceramic membranes. Throughout, the contributions clearly point out the intimate links between structure, properties and applications of these materials, making this an invaluable tool for materials scientists and for catalytic and physical chemists.

Download or read book Tuning Structural and Physical Properties Via A site Doping in Perovskite type Transition Metal Oxides written by Hamoud H. Somaily and published by . This book was released on 2018 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the structure-property relationship of two important classes of transition metal oxides (the perovskite-type A-site substituted titanates (Sr[sub 1-x-y]Ca[sub x]Nd[sub y])TiO[sub 3] and manganites (Sr[sub 1-x]Ba[sub x])MnO[sub 3]). A thorough evaluation is provided of their potential for prospective technological applications in heat recycling and information technology by examining the thermoelectric and multiferroic prop- erties, respectively. In the titanate compounds, we doped on the A-site with small rare earth ions in order to generate mixed valent transition metals to increase band filling while the Ca doping maintained fixed levels of distortions. In the case of the manganites, A-site Sr ions were substituted with large Ba ions for the purpose of increasing the materials strain and to promote ferroelectricity. Crystal structure was investigated using high-resolution neutron powder diffraction as a function of temperature and Nd/Ba doping. In the titanates, two series were synthesized and designed to have a nominally constant tolerance factor at room temperature. We determine the room temperature structures as tetragonal I4/mcm and orthorhombic Pbnm for the Sr-rich and Ca-rich series, respectively. Three low temperature orthorhombic structures, Pbnm, Ibmm and Pbcm were also observed for the Sr-rich series; whereas, the symmetry of the Ca-rich series remained unchanged throughout the full measured temperature range. Thermoelectricity in ternary (Sr[sub 1-x-y]Ca[sub x]Nd[sub y])TiO[sub 3] perovskites was investigated. The double substitution at the A-site maintained a fixed crystal distortion while Nd3+ doping modified the electronic properties of the materials via increased band filling. Unique compositions of cations allowed for increased A-site atomic mass disorder and the lattice thermal conductivity was significantly suppressed to values as low as ~ 1.5 W/K.m in some samples, approaching amorphous Silicon limit. Charge doping via balanced formation of Ti^3+ at the B-site has transformed materials into n-type semi-conductors. I examined the range of applicability of various conduction models, viz., variable range hopping, semiconductor-type conductivity across band gap, and small polaron hopping for the best description of the temperature variation of measured resistivity. We succeeded in achieving a relatively high figure of merit ZT=0.07 at ~ 400 K in the Sr-rich Sr[sub 0.76]Ca[sub 0.16]Nd[sub 0.08]TiO[sub 3] composition which is comparable to that of the best n-type TE SrTi[sub 0.80]Nb[sub 0.20]O[sub 3] oxide material reported to date. With an enhanced Seebeck coefficient at elevated temperatures and reduced thermal conductivity, we predict that Sr[sub 0.76]Ca[sub 0.16]Nd[sub 0.08]TiO[sub 3] and similar compositions have the potential to become some of the best materials in their class of thermoelectric oxides. We also report the structure-property phase diagram of unique single-ion type-1 multiferroic pseudocubic Sr1-xBaxMnO3 perovskites. Employing a specially designed multi-step reduction-oxidation synthesis technique, we have synthesized previously unknown Sr[sub 1-x]Ba[sub x]MnO[sub 3] compositions in their polycrystalline form with a significantly extended Ba solubility limit that is only rivaled by a very limited number of crystals and thin films grown under non-equilibrium conditions. Understanding the multiferroic interplay with structure in Sr[sub 1-x]Ba[sub x]MnO[sub 3] is of great importance as it opens the door wide to the development of newer materials from the parent (AA')(BB')O3 system with enhanced properties. To this end, using a combination of time-of-flight neutron and synchrotron x-ray scattering techniques, we determined the exact structures and quantified the Mn and oxygen polar distortions above and below the ferroelectric Curie temperature TC and the Neel temperature TN. In its ferroelectric state, the system crystalizes in the noncentrosymmetric tetragonal P4mm space group which gives rise to a large electric dipole moment PS, in the z-direction, of 18.4 and 29.5 microC/cm2 for x = 0.43 and 0.45, respectively. The two independently driven ferroelectric and magnetic order parameters are single-handedly accommodated by the Mn sublattice leading to a novel strain-assisted multiferroic behavior in agreement with many theoretical predictions. Our neutron diffraction results demonstrate the large and tunable suppression of the ferroelectric order at the onset of AFM ordering and confirm the coexistence and strong coupling of the two ferroic orders below T[sub N]. The refined magnetic moments confirm the strong covalent bonding between Mn and the oxygen anions which is necessary for stabilizing the ferroelectric phase.

Download or read book Johann Martin Usteri written by Albert Nägeli and published by . This book was released on 1907 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High pressure Synthesis of the 4d and 5d Transition metal Oxides with the Perovskite and the Perovskite related Structure and Their Physical Properties written by Jinguang Cheng and published by . This book was released on 2010 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Walker-type multianvil high-pressure facility is capable of high-pressure syntheses and measurements beyond 10 GPa and has been utilized in my research to synthesize the 4d Ruthenium and Rhodium and the 5d Iridium oxides with the perovskite-related structures. Under high-pressure and high-temperature conditions, these families of oxides can be enlarged to a great extent so that enables us not only to address the long-standing problem about ferromagnetism in the perovskite ruthenates but also explore new phenomena associated with the structural and electronic properties in the iridates and rhodates. In the perovskite ruthenates ARuO3 (A= Ca, Sr, and Ba), a systematic study of the variations of the ferromagnetic transition temperature T[subscript c] and the critical isothermal magnetization as a function of the average A-site cation size and the size variance as well as external high pressures reveals explicitly the crucial role of the local lattice strain and disorder on T[subscript c] and the nature of the localized-electron ferromagnetism. However, such a steric effect is dominated by the electronic effect in another perovskite ruthenate PbRuO3, which is a paramagnetic metal down to 1.8 K and undergoes a first-order structural transition to a low-temperature Imma phase at Tt [almost equal to] 90 K. Bandwidth broadening due to orbital hybridization between Pb-6s and Ru-4d plays an important role in suppressing the ferromagnetism in the Sr1-zPbzRuO3 system. The high-pressure sequence of the 9R-BaIrO3 was explored and three more polytypes, i.e. 5H, 6H and 3C, were identified under 10 GPa. With increasing fraction of the corner- to face-sharing IrO6/2 octahedra, the ground states of BaIrO3 evolve from a ferromagnetic insulator with T[subscript c] [almost equal to] 180 K in the 9R phase to a ferromagnetic metal with T[subscript c] [almost equal to] 50 K in the 5H phase, and finally to an exchange-enhanced paramagnetic metal near a quantum critical point in the 6H phase. In addition to the perovskite SrRhO3, a new 6H polytype was synthesized for the first time under high pressure and a pressure-temperature phase diagram was given for the 6H-perovskite transformation. Restoration of the Curie-Weiss behavior in the high-temperature magnetic susceptibility [chi](T) of the perovskite SrRhO3 resolves the puzzle about unusual dependence of [chi]−1 [symbol] T2 reported earlier and highlights the importance of spin-orbit coupling in the 4d and 5d transition-metal oxides.

Download or read book Bibliography written by Pierre Villars and published by Walter de Gruyter. This book was released on 2012-12-21 with total page 1827 pages. Available in PDF, EPUB and Kindle. Book excerpt: By browsing about 10 000 000 scientific articles of over 200 major journals mainly in a 'cover to cover approach' some 200 000 publications were selected. The extracted data is part of the following fundamental material research fields: crystal structures (S), phase diagrams (also called constitution) (C) and the comprehensive field of intrinsic physical properties (P). This work has been done systematically starting with the literature going back to 1900. The above mentioned research field codes (S, C, P) as well as the chemical systems investigated in each publication were included in the present work. The aim of the Inorganic Substances Bibliography is to provide researchers with a comprehensive compilation of all up to now published scientific publications on inorganic systems in only three handy volumes.

Download or read book High Temperature Magnetic Properties of Transition Metal Oxides with Perovskite Structure written by Dinesh Baskar and published by . This book was released on 2008 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Fundamentals and Challenges of Oxide Materials written by Mihail Lungu and published by Cambridge Scholars Publishing. This book was released on 2022-12-15 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxide materials are the most common natural materials and are used in various technical and biomedical applications. Oxides are involved in industry to produce energy, various sensors, catalysts and electronic devices. They also find uses in medical applications, personal and home care products, and construction in manufacturing sealants, adhesives, paints and coating. The application of oxide materials will continue to grow in the future and their use as nanostructured materials will open new horizons. This book presents the fundamentals of oxide powders, undoped or doped with metal ions (having spinel, perovskite or crednerite type structure) and obtained by different methods, establishing a connection between the structure and their electromagnetic properties, with the purpose to be used in technological and biomedical applications.

Download or read book Design Synthesis Crystal Structure and Magnetic Properties of Novel Osmium based B site Ordered Double Perovskites written by David D. Russell and published by . This book was released on 2016 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Transition metal oxides (TMOs) with face centered cubic arrangement of magnetic ions are composed of triangular sub-lattices. When antiferromagnetic (AFM) interactions of the same strengths between all three pathways in triangular settings are in place, spin constraints cannot be fulfilled simultaneously and the system undergoes geometric magnetic frustration (GMF). The purpose of the work presented in this thesis is to better understand the criteria for a system to undergo GMF. To achieve this, the novel B-site ordered double perovskites Ca2ScOsO6 and Ca2.2Mg0.8 OsO6 were synthesized in polycrystalline form utilizing the conventional solid-state method. The crystal structure of these compounds were characterized through X-ray diffraction, and magnetic properties were explored through magnetic susceptibility measurements. Employing the spin-dimer analysis method, relative magnetic exchange interactions were calculated and modeled. These novel osmium-based B-site ordered double perovskites were then compared to isostructural compounds to study the effects of the osmium oxidation state on crystal structure and the exhibited properties.

Download or read book Journal of the Physical Society of Japan written by and published by . This book was released on 2007 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tuning Electronic Interface Reconstruction and Magnetic Reversal in Perovskite Oxide Exchange Spring Heterostructures written by Alexander Michael Kane and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perovskite ABO3 oxides, where A is typically a rare-earth or alkali-earth metal and B a transition metal, are attractive candidates for implementation in next generation microelectronic devices. They combine a wide range of fascinating, technologically-relevant functional properties such as ferromagnetism, ferroelectricity, and superconductivity, with a unique sensitivity to external stimuli. Their charge, orbital, lattice, and spin degrees of freedom are readily manipulated by chemical doping, external magnetic and electric fields, lattice strain, and electronic/magnetic reconstruction at thin film interfaces. Exchange springs comprise a class of materials that combines the high saturation magnetization of soft ferromagnets with the high coercivity of hard ferromagnets, which were initially proposed as candidates for improved permanent magnets and later for use in heat-assisted magnetic recording devices. While metallic exchange spring systems have been extensively studied, their oxide counterparts remain relatively unexplored. This dissertation is primarily focused on investigating and building our understanding of the electronic/magnetic reconstruction that occurs in perovskite oxide exchange spring bilayers, and how it can be used to tune relevant magnetic parameters such as coercivity and exchange bias. Soft x-ray magnetic spectroscopy was used to elucidate the multifaceted behavior at the interfaces of La0.7Sr0.3CoO3 (LSCO)/La0.7Sr0.3MnO3 (LSMO) bilayers, which was applied to a wedge sample geometry to eliminate the potential variation and possible deviations from targeted film thicknesses across multiple samples. Two separate wedge bilayers were measured, one each of constant LSMO/LSCO layer thickness and varying LSCO/LSMO thickness. In the bilayer with changing LSCO layer thickness, we observe a gradual decrease in Co2+ ion concentration at the interface and opposing trends between the soft FM layer exchange bias and coercivity. On the other hand, as the LSMO layer thickness was changed, the LSCO magnetization was found to originate from a mixture of Co3+/Co4+ and Co2+ ions for thinner LSMO, and shift to a primarily Co2+ signal as the LSMO thickness was increased, effectively reducing the critical thickness required for Co3+/Co4+ - type magnetism in ultrathin LSCO films. These studies highlight the extreme sensitivity and tunability of perovskite systems; the magnetic behavior of this coupled system was found to depend on both layer thicknesses, with the ability to tune the exchange bias and coercivity of both layers by via careful consideration of layer thickness. Our LSCO/LSMO exchange spring bilayers, much like their metallic analogs, are expected to exhibit a gradual unwinding of the soft layer magnetization due to the unidirectional anisotropy imposed by the hard magnetic layer. Such an effect may produce a non-collinear magnetic spin structure at small reversal fields whose magnetization vector lies in the plane of the film, yet neither completely parallel to the applied field nor antiparallel (hard FM layer). However, obtaining a full depth and spatial resolution of sample magnetization is a challenge. In this dissertation, polarized neutron reflectometry (PNR) was used for this purpose, where we observe that increasing the LSCO layer thickness in the LSCO/LSMO exchange spring system decreases the magnetic moment of the interface LSCO layer, which matches the decrease in Co2+ concentration observed in the LSCO wedge bilayer spectroscopy data. Furthermore, contrary to x-ray characterization, PNR is sensitive to the oxygen content within the films. We also observe a higher concentration of oxygen vacancies at the LSCO/LSMO interface, which provides an additional contribution to the Co2+ ion formation in the LSCO/LSMO bilayer system. Because the magnetic properties of LSCO/LSMO bilayers and perovskite systems in general are highly dependent on the valence state concentration of the constituent B-site cations, manipulating charge transfer provides a means to predict and control the functional properties in oxide multilayers. To this end, the effects of such interface charge transfer reactions were further investigating by incorporating an intentional mixture of Co/Mn ions on the perovskite B-site in the double perovskite La1.4Sr0.6CoMnO6 (LSCMO) and exploring the varying effects of its interfaces with LSCO and LSMO. We found that the LSCMO layer is uniquely sensitive to the layer choice and growth order; an LSCMO/LSMO bilayer amplifies the Co2+ signal and maintains the low coercivity/high saturation magnetization of the LSCMO layer, while an LSCO/LSCMO bilayer reduces the Co2+ concentration in favor of Co3+ and results in "LSCO-like" hard FM layer behavior with high coercivity and low magnetization. When both effects are present in a trilayer sample, the LSCO/LSCMO layer was found to be the much stronger of the two interface reactions. This system provides fundamental insight into the nature of charge transfer reactions at perovskite interfaces and helps to build a predictive model for arbitrary interface architectures.