Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The perovskite unit cell is the fundamental building block of many functional materials. The manipulation of this crystal structure is known to be of central importance to controlling many technologically promising phenomena related to superconductivity, multiferroicity, mangetoresistivity, and photovoltaics. The broad range of properties that this structure can exhibit is in part due to the centrally coordinated octahedra bond flexibility, which allows for a multitude of distortions from the ideal highly symmetric structure. However, continuous and fine manipulation of these distortions has never been possible. Here, we show that controlled insertion of He atoms into an epitaxial perovskite film can be used to finely tune the lattice symmetry by modifying the local distortions, i.e., octahedral bonding angle and length. Orthorhombic SrRuO3 films coherently grown on SrTiO3 substrates are used as a model system. Implanted He atoms are confirmed to induce out-of-plane strain, which provides the ability to controllably shift the bulk-like orthorhombically distorted phase to a tetragonal structure by shifting the oxygen octahedra rotation pattern. Lastly, these results demonstrate that He implantation offers an entirely new pathway to strain engineering of perovskite-based complex oxide thin films, useful for creating new functionalities or properties in perovskite materials.
Author: Tamalika Banerjee
Publisher: CRC Press
ISBN: 0429886896
Category : Science
Languages : en
Pages : 207
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Book Description
Oxide materials have been used in mainstream semiconductor technology for several decades and have served as important components, such as gate insulators or capacitors, in integrated circuits. However, in recent decades, this material class has emerged in its own right as a potential contender for alternative technologies, generally designated as ‘beyond Moore’. The 2004 discovery by Ohtomo and Hwang was a global trendsetter in this context. It involved observing a two-dimensional, high-mobility electron gas at the heterointerface between two insulating oxides, LaAlO3 and SrTiO3, supported by the rise of nascent deposition and growth-monitoring techniques, which was an important direction in materials science research. The quest to understand the origin of this unparalleled physical property and to find other emergent properties has been an active field of research in condensed matter that has united researchers with expertise in diverse fields such as thin-film growth, defect control, advanced microscopy, semiconductor technology, computation, magnetism and electricity, spintronics, nanoscience, and nanotechnology.
Author: Jose Luis Clabel Huaman
Publisher: Elsevier
ISBN: 0323907105
Category : Technology & Engineering
Languages : en
Pages : 626
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Book Description
Perovskite-based ceramics are a significant class of innovative materials with fascinating physical properties, which are now receiving intensive research attention in condensed matter physics and in the area of practical device applications. Perovskite Ceramics provides a state-of-the-art review on the latest advances in perovskite-based ceramic materials, as well as the development of devices from these materials for different applications. Perovskite Ceramics: Recent Advances and Emerging Applications is divided into two main parts. The first part focuses on the basics of perovskite-based ceramic materials and includes chapters on the fundamentals, synthesis and processing, characterization, and properties of these materials. Chapters are also included on bulk and thin materials, phase transitions, polaronic effects and the compensation and screening of ferroelectricity. This section will allow the reader to familiarize themselves with the standard traditional approach, but it will also introduce new concepts that are fast evolving in this field. The second part presents an extensive review of up-to-date research on new and innovative advances in perovskite-based ceramic materials. Chapters cover multiferroic applications, lead-free perovskites, energy storage applications, perovskite-based memories, light manipulation and spectral modifications, and solar cells and fuel cells. All these fields of research are rapidly evolving, so the book acts a platform to showcase latest results on optical strategies and materials for light manipulation, and spectral up- and down-conversion too (mainly rare earth doped oxides and complexes). The book will be an essential reference resource for academic and industrial researchers working in materials research and development particularly in functional and oxide ceramics and perovskites. - A comprehensive and systematic review of advanced research in perovskite-based ceramics - Covers both oxide and halide perovskites, their synthesis, processing, properties and applications - Presents advanced methods of synthesis as well as latest applications - Discusses all aspects from theory to production - Covers the most important advances both in terms of new materials and application strategies
Author: Amber K. Choquette
Publisher:
ISBN:
Category : Ferroelectricity
Languages : en
Pages : 376
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Book Description
Perovskite oxides, which take the chemical formula ABO3, are a very versatile and interesting materials family, exhibiting properties that include ferroelectricity, ferromagnetism, mixed ionic/electronic conductivity, metal-insulator behavior and multiferroicity. Key to these functionalities is the network of BO6 corner-connected octahedra, which are known to distort and rotate, directly altering electronic and ferroic properties. By controlling the BO6 octahedral distortions and rotations through cationic substitutions, the use of strain engineering, or through the formation of superlattice structures, the functional properties of perovskites can be tuned. Motivating the use of structure-driven design in oxide heterostructures is the prediction of hybrid improper ferroelectricity in A'BO3/ABO3 superlattices. Two key design rules to realizing hybrid improper ferroelectricity are the growth of high quality superlattice structures with odd periodicities of the A / A' layers, and the control of the octahedral rotation pattern. My work explores the rotational response in perovskite oxides to strain and interface effects in thin films of RFeO3 (R = La, Eu). I demonstrate a synchrotron x-ray diffraction technique to identify the rotation pattern that is present in the films. I then establish substrate imprinting as a key tool for controlling the rotation patterns in heterostructures, providing a means to realize the necessary structural variants of the predicted hybrid improper ferroelectricity in superlattices. In addition, by pairing measured diffraction data with a structure factor calculation, I demonstrate how one can extract both A-site and oxygen atomic positions in single crystal perovskite oxide films. Finally, I show results from (LaFeO3)n/(EuFeO3)n superlattices (n = 1-5), synthesized to test the motivating predictions of hybrid improper ferroelectricity in oxide superlattices.
Author: David Jamieson
Publisher: CRC Press
ISBN: 1040153828
Category : Science
Languages : en
Pages : 174
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Book Description
This book explores new experimental techniques and theoretical models to deepen an understanding of radiation effects and ion interaction processes in order to design materials for devices for the emerging quantum technology era. Applications include tailored sensors that respond to ionizing radiation and other electromagnetic phenomena; sensors with high radiation hardness; and materials that contain specific engineered defects with desirable optical, magnetic, or electrical properties. The chapters detail direct experimental investigations into the dynamics of radiation-induced defects, including their generation, annihilation, and transformation, on a time scale ranging from femto-seconds to seconds which requires a more detailed understanding to develop the potential of ion beams for the new technology era. It will be a valuable reference for graduate students and researchers that employ ion beams and want to engage in quantum technologies. The book will also be of interest to scientists and engineers from industry that want to make use of ion beams in quantum technologies or learn more about the potential use of ion beams in the field. Key Features: • Provides a comprehensive introduction to this exciting and growing field of research. • Up-to-date with the latest cutting-edge research and practical guidance for researchers and those in industry to apply to their work. • Edited by established authorities, with chapter contributions from subject-area specialists.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
We report on the use of helium ion implantation to independently control the out-of-plane lattice constant in epitaxial La0.7Sr0.3MnO3 thin films without changing the in-plane lattice constants. The process is reversible by a vacuum anneal. Resistance and magnetization measurements show that even a small increase in the out-of-plane lattice constant of less than 1% can shift the metal-insulator transition and Curie temperatures by more than 100 °C. Unlike conventional epitaxy-based strain tuning methods which are constrained not only by the Poisson effect but by the limited set of available substrates, the present study shows that strain can be independently and continuously controlled along a single axis. This permits novel control over orbital populations through Jahn-Teller effects, as shown by Monte Carlo simulations on a double-exchange model. As a result, the ability to reversibly control a single lattice parameter substantially broadens the phase space for experimental exploration of predictive models and leads to new possibilities for control over materials' functional properties.
Author: Hamoud H. Somaily
Publisher:
ISBN: 9780438032682
Category : Physics
Languages : en
Pages : 162
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Book Description
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.
Author: Deepam Maurya
Publisher: Woodhead Publishing
ISBN: 0081028792
Category : Technology & Engineering
Languages : en
Pages : 374
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Book Description
The need to more efficiently harvest energy for electronics has spurred investigation into materials that can harvest energy from locally abundant sources. Ferroelectric Materials for Energy Harvesting and Storage is the first book to bring together fundamental mechanisms for harvesting various abundant energy sources using ferroelectric and piezoelectric materials. The authors discuss strategies of designing materials for efficiently harvesting energy sources like solar, wind, wave, temperature fluctuations, mechanical vibrations, biomechanical motion, and stray magnetic fields. In addition, concepts of the high density energy storage using ferroelectric materials is explored. Ferroelectric Materials for Energy Harvesting and Storage is appropriate for those working in materials science and engineering, physics, chemistry and electrical engineering disciplines. - Reviews wide range of energy harvesting including solar, wind, biomechanical and more - Discusses ferroelectric materials and their application to high energy density capacitors - Includes review of fundamental mechanisms of energy harvesting and energy solutions, their design and current applications, and future trends and challenges
Author: Gertjan Koster
Publisher: Elsevier
ISBN: 1782422552
Category : Technology & Engineering
Languages : en
Pages : 505
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Book Description
The atomic arrangement and subsequent properties of a material are determined by the type and conditions of growth leading to epitaxy, making control of these conditions key to the fabrication of higher quality materials. Epitaxial Growth of Complex Metal Oxides reviews the techniques involved in such processes and highlights recent developments in fabrication quality which are facilitating advances in applications for electronic, magnetic and optical purposes. Part One reviews the key techniques involved in the epitaxial growth of complex metal oxides, including growth studies using reflection high-energy electron diffraction, pulsed laser deposition, hybrid molecular beam epitaxy, sputtering processes and chemical solution deposition techniques for the growth of oxide thin films. Part Two goes on to explore the effects of strain and stoichiometry on crystal structure and related properties, in thin film oxides. Finally, the book concludes by discussing selected examples of important applications of complex metal oxide thin films in Part Three. Provides valuable information on the improvements in epitaxial growth processes that have resulted in higher quality films of complex metal oxides and further advances in applications for electronic and optical purposes Examines the techniques used in epitaxial thin film growth Describes the epitaxial growth and functional properties of complex metal oxides and explores the effects of strain and defects
Author: Tze-Chien Sum
Publisher: John Wiley & Sons
ISBN: 3527341110
Category : Technology & Engineering
Languages : en
Pages : 312
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Book Description
Real insight from leading experts in the field into the causes of the unique photovoltaic performance of perovskite solar cells, describing the fundamentals of perovskite materials and device architectures. The authors cover materials research and development, device fabrication and engineering methodologies, as well as current knowledge extending beyond perovskite photovoltaics, such as the novel spin physics and multiferroic properties of this family of materials. Aimed at a better and clearer understanding of the latest developments in the hybrid perovskite field, this is a must-have for material scientists, chemists, physicists and engineers entering or already working in this booming field.
