Epitaxial thin films and heterostructures based on perovskite oxides have attracted significant attention in physics since perovskites exhibit an enormous range of electrical, magnetic, and optical properties, making them exciting systems for studies of the fundamental physical mechanisms of interactions between electron, lattice, and spin degrees of freedom. This dissertation has been focused on ferroelectricity in low-dimensional ferroelectric materials using ultra-thin ferroelectric epitaxial films (BaTiO3) with a metallic electrode (SrRuO3) by studying polarized ordering of the crystal structure and electronic transport through the films. High quality and highly oxidized epitaxial films are a prerequisite for the clear observation of physical properties such as ferroelectricity which depends on a sensitive balance of lattice structure, dynamics, and charge distribution. Measurements in low dimensional, ultra-thin films require a controlled surface status through in-situ characterization. As is demonstrated here, fundamental physical phenomena on surfaces and in ultra-thin films are easily modified due to reactivity in ambient air, even for oxide materials generally considered inert. This study is centered on in-situ low energy electron diffraction and scanning tunneling spectroscopy of BaTiO3 films grown on SrRuO3 electrodes on a SrTiO3 substrate. Results show out-of-plane polarized structure and polarization switching, which provide evidence of ferroelectricity in films down to 4 ML. Surface reconstruction in 1-2 ML thick BaTiO3 films is seriously affected by the interface between BaTiO3 films and SrRuO3 bottom electrode. Our observation in epitaxial BaTiO3 films indicates the existence of ferroelectricity with a lower limit (4 ML) for the minimum thickness than theoretical expectation (6 ML), which results from the difference of film stress, termination on films, and depolarizing screening.

Metal Oxide-Based Thin Film Structures: Formation, Characterization and Application of Interface-Based Phenomena bridges the gap between thin film deposition and device development by exploring the synthesis, properties and applications of thin film interfaces. Part I deals with theoretical and experimental aspects of epitaxial growth, the structure and morphology of oxide-metal interfaces deposited with different deposition techniques and new developments in growth methods. Part II concerns analysis techniques for the electrical, optical, magnetic and structural properties of thin film interfaces. In Part III, the emphasis is on ionic and electronic transport at the interfaces of Metal-oxide thin films. Part IV discusses methods for tailoring metal oxide thin film interfaces for specific applications, including microelectronics, communication, optical electronics, catalysis, and energy generation and conservation. This book is an essential resource for anyone seeking to further their knowledge of metal oxide thin films and interfaces, including scientists and engineers working on electronic devices and energy systems and those engaged in research into electronic materials. - Introduces the theoretical and experimental aspects of epitaxial growth for the benefit of readers new to the field - Explores state-of-the-art analysis techniques and their application to interface properties in order to give a fuller understanding of the relationship between macroscopic properties and atomic-scale manipulation - Discusses techniques for tailoring thin film interfaces for specific applications, including information, electronics and energy technologies, making this book essential reading for materials scientists and engineers alike

Using the deposition method best suited for depositing an oxide thin film can be the difference between measuring the intrinsic properties of the thin film and measuring extrinsic properties arising from defects, impurity phases, and contamination. In this work, unique synthesis routes for the deposition of three epitaxial oxide thin films is presented. Applying these new routes, new material properties were able to be discerned that had been concealed in thin films deposited utilizing conventional methods. Dual off-axis RF sputtering of Bi-rich BiFeO3̳ targets was employed to deposit a 1 [mu]m-thick multiferroic BiFeO3̳ film on various (111)p̳c̳-orientated substrates with cubic and orthorhombic symmetries. Using non-resonant x-ray magnetic scattering (NXMS) and neutron diffraction, the magnetic domain populations in the BiFeO3̳ were measured. We found that growing on reduced-symmetry substrate NdGaO3̳ (011)o̳, yields a BiFeO3̳ film with a single ferroelectric, structural, and magnetic domain consistent across the whole sample. The single domain remains stable even after switching a region of the sample ferroelectrically up to 10,000 times. Using NXMS polarimetry we confirm that there is a change in the magnetic polarity of the BiFeO3̳ domain after ferroelectric switching, demonstrating the coupling of the magnetic and ferroelectric orders in monodomain (111)p̳c̳-orientated BiFeO3 ̳ thin films. Using reactive RF sputtering of a pure Fe target, phase pure deposition of antiferromagnetic insulator [alpha]-Fe2O3̳ was achieved. SQUID magnetometry confirms the absence of any ferromagnetic minority domains in the film. We showed that the Morin transition temperature, above which [alpha]-Fe2̳O3̳ has a weak canted moment, decreases when reducing the thickness of the film. For films 10 nm and thinner, the Morin transition was suppressed completely. Using the XMLD contrast of the 10 nm-thick [alpha]-Fe2̳O3̳ film, X-ray Photoemission Electron Microscopy (PEEM) measurements uncovered a complex mosaic of sub-micron size antiferromagnetic domains connected by a network of antiferromagnetic spin vortices. The vortices were mostly found in vortex/antivortex pairs which could be annihilated through the application of an external magnetic field. When a 1 nm-thick Co layer was overlayed, the mosaic of domains present in the [alpha]-Fe2̳O3̳ was coupled to the Co which takes on the same mosaic pattern. Pulsed laser deposition of SrO and chemical vapor deposition of a TiO2̳ precursor gas were used simultaneously to deposit high quality SrTiO3 thin films in a hybrid deposition technique we called metal-organic pulsed laser deposition (MOPLD). We demonstrated a conductive 2-dimensional electron gas (2DEG) at the interface between MOPLD-grown SrTiO3 and PLD-grown LaAlO3̳, indicative that the SrTiO3̳ thin film is highly stoichiometric. The increased stoichiometry control afforded by MOPLD also grants the ability to control the point defects in the system. By decreasing the abundance of point defects, quantum properties of SrTiO3̳ become accessible.

Our understanding and control of epitaxial oxide heterostructures has progressed along multiple frontiers including magnetic, dielectric, ferroelectric, and superconducting oxide materials. This has resulted in both independent rediscovery and the successful borrowing of ideas from ceramic science, solid-state physics, and semiconductor epitaxy. A new field of materials science has emerged which aims at the use of the intrinsic properties of various oxide materials in single-crystal thin-film form. Exploiting the potential of these materials, however, will only be possible if many fundamental and engineering questions can be answered. This book represents continued progress toward fulfilling that promise. Technical information on epitaxial oxide thin films from industry, academia and government laboratories is presented. Topics include: dielectrics; ferroelectrics; optics; superconductors; magnetics; magnetoresistance.

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

The edited volume "Epitaxy" is a collection of reviewed and relevant research chapters, offering a comprehensive overview of recent developments in the field of materials science. The book comprises single chapters authored by various researchers and edited by an expert active in this research area. All chapters are complete in themselves but are united under a common research study topic. This publication aims at providing a thorough overview of the latest research efforts by international authors in the field of materials science as well as opening new possible research paths for further developments.

This two volume set reviews the key issues in processing and characterization of nanoscale ferroelectrics and multiferroics, and provides a comprehensive description of their properties, with an emphasis in differentiating size effects of extrinsic ones like boundary or interface effects. Recently described nanoscale novel phenomena are also addressed. Organized into three parts it addresses key issues in processing (nanostructuring), characterization (of the nanostructured materials) and nanoscale effects. Taking full advantage of the synergies between nanoscale ferroelectrics and multiferroics, the text covers materials nanostructured at all levels, from ceramic technologies like ferroelectric nanopowders, bulk nanostructured ceramics and thick films, and magnetoelectric nanocomposites, to thin films, either polycrystalline layer heterostructures or epitaxial systems, and to nanoscale free standing objects with specific geometries, such as nanowires and tubes at different levels of development. This set is developed from the high level European scientific knowledge platform built within the COST (European Cooperation in Science and Technology) Action on Single and multiphase ferroics and multiferroics with restricted geometries (SIMUFER, ref. MP0904). Chapter contributors have been carefully selected, and have all made major contributions to knowledge of the respective topics, and overall, they are among most respected scientists in the field.

Solution Processed Metal Oxide Thin Films for Electronic Applications discusses the fundamentals of solution processing materials chemistry techniques as they are applied to metal oxide materials systems for key device applications. The book introduces basic information (materials properties, materials synthesis, barriers), discusses ink formulation and solution processing methods, including sol-gel processing, surface functionalization aspects, and presents a comprehensive accounting on the electronic applications of solution processed metal oxide films, including thin film transistors, photovoltaic cells and other electronics devices and circuits. This is an important reference for those interested in oxide electronics, printed electronics, flexible electronics and large-area electronics. - Provides in-depth information on solution processing fundamentals, techniques, considerations and barriers combined with key device applications - Reviews important device applications, including transistors, light-emitting diodes, and photovoltaic cells - Includes an overview of metal oxide materials systems (semiconductors, nanomaterials and thin films), addressing materials synthesis, properties, limitations and surface aspects

As a result of the progress towards, and potential realized in electronic and optical device applications, the interest in epitaxial oxide thin films continue to flourish. The understanding of epitaxial oxide heterostructures has progressed, including magnetic, magnetoresistive, dielectric, ferroelectric and superconducting oxide materials. This book focuses on the fundamental issues of oxide epitaxy, microstructural evolution in epitaxy, and physical properties of epitaxial oxide thin films and how these issues relate to device applications. The book provides a vehicle through which groups of scientists working on a set of diverse phenomena could interact and present findings on very common specific themes involving similar materials. Due to the explosive growth of work in the area of colossal magnetoresistive (CMR) materials, especially in epitaxial form, the book also offers a forum to critically examine the fundamental nature of CMR in epitaxial oxide thin films and the relationship between CMR and defect structure. Other areas of emphasis include: ferroelectric memories, nonlinear optical waveguides, microwave electronics and magnetic oxide thin films.