Domain Walls

As the first of its kind, this book identifies major questions and challenges that will influence research on domain walls in the years to come.

Technological evolution and revolution are both driven by the discovery of new functionalities, new materials and the design of yet smaller, faster, and more energy-efficient components. Progress is being made at a breathtaking pace, stimulated by the rapidly growing demand for more powerful and readily available information technology. High-speed internet and data-streaming, home automation, tablets and smartphones are now "necessities" for our everyday lives. Consumer expectations for progressively more data storage and exchange appear to be insatiable. Oxide electronics is a promising and relatively new field that has the potential to trigger major advances in information technology. Oxide interfaces are particularly intriguing. Here, low local symmetry combined with an increased susceptibility to external fields leads to unusual physical properties distinct from those of the homogeneous bulk. In this context, ferroic domain walls have attracted recent attention as a completely new type of oxide interface. In addition to their functional properties, such walls are spatially mobile and can be created, moved, and erased on demand. This unique degree of flexibility enables domain walls to take an active role in future devices and hold a great potential as multifunctional 2D systems for nanoelectronics. With domain walls as reconfigurable electronic 2D components, a new generation of adaptive nano-technology and flexible circuitry becomes possible, that can be altered and upgraded throughout the lifetime of the device. Thus, what started out as fundamental research, at the limit of accessibility, is finally maturing into a promising concept for next-generation technology.

Using the nano metric resolution of atomic force microscopy techniques, this work explores the rich fundamental physics and novel functionalities of domain walls in ferroelectric materials, the nano scale interfaces separating regions of differently oriented spontaneous polarization. Due to the local symmetry-breaking caused by the change in polarization, domain walls are found to possess an unexpected lateral piezoelectric response, even when this is symmetry-forbidden in the parent material. This has interesting potential applications in electromechanical devices based on ferroelectric domain patterning. Moreover, electrical conduction is shown to arise at domain walls in otherwise insulating lead zirconate titanate, the first such observation outside of multiferroic bismuth ferrite, due to the tendency of the walls to localize defects. The role of defects is then explored in the theoretical framework of disordered elastic interfaces possessing a characteristic roughness scaling and complex dynamic response. It is shown that the heterogeneous disorder landscape in ferroelectric thin films leads to a breakdown of the usual self-affine roughness, possibly related to strong pinning at individual defects. Finally, the roles of varying environmental conditions and defect densities in domain switching are explored and shown to be adequately modelled as a competition between screening effects and pinning.

Magnetic Domain Walls in Bubble Materials covers the physics of domain walls in bubble domain materials. The book describes the microscopic origins and characteristics of the material parameters; the principles of domain statics and the Landau-Lifshitz equation, which is the basic equation of magnetization dynamics; and its physical significance. The text then discusses the experimental techniques, both static and dynamic, used in studying domain walls; the static internal structure of bubble-domain walls; the Bloch-wall dynamics based on one-dimensional solutions of the Landau-Lifshitz equation; and the wall-motion theory. The theory to low velocity phenomena in domain walls containing vertical Bloch; high-velocity radial and quasi-planar wall motions; and nonlinear bubble translation including the implications of the theory for bubble motion in devices, are also considered. The book further surveys special phenomena involving vibrations and wave motions of walls, and the effects of microwave-frequency fields on walls. Engineers and materials researchers involved in the development of practical bubble devices will find the book invaluable.

At present, the marketplace for professionals, researchers, and graduate students in solid-state physics and materials science lacks a book that presents a comprehensive discussion of ferroelectrics and related materials in a form that is suitable for experimentalists and engineers. This book proposes to present a wide coverage of domain-related issues concerning these materials. This coverage includes selected theoretical topics (which are covered in the existing literature) in addition to a plethora of experimental data which occupies over half of the book. The book presents experimental findings and theoretical understanding of ferroic (non-magnetic) domains developed during the past 60 years. It addresses the situation by looking specifically at bulk crystals and thin films, with a particular focus on recently-developed microelectronic applications and methods for observations of domains with techniques such as scanning force microscopy, polarized light microscopy, scanning optical microscopy, electron microscopy, and surface decorating techniques. "Domains in Ferroic Crystals and Thin Films" covers a large area of material properties and effects connected with static and dynamic properties of domains, which are extremely relevant to materials referred to as ferroics. In other textbooks on solid state physics, one large group of ferroics is customarily covered: those in which magnetic properties play a dominant role. Numerous books are specifically devoted to magnetic ferroics and cover a wide spectrum of magnetic domain phenomena. In contrast, "Domains in Ferroic Crystals and Thin Films" concentrates on domain-related phenomena in nonmagnetic ferroics. These materials are still inadequately represented in solid state physics textbooks and monographs.

The Springer Handbook of Experimental Solid Mechanics documents both the traditional techniques as well as the new methods for experimental studies of materials, components, and structures. The emergence of new materials and new disciplines, together with the escalating use of on- and off-line computers for rapid data processing and the combined use of experimental and numerical techniques have greatly expanded the capabilities of experimental mechanics. New exciting topics are included on biological materials, MEMS and NEMS, nanoindentation, digital photomechanics, photoacoustic characterization, and atomic force microscopy in experimental solid mechanics. Presenting complete instructions to various areas of experimental solid mechanics, guidance to detailed expositions in important references, and a description of state-of-the-art applications in important technical areas, this thoroughly revised and updated edition is an excellent reference to a widespread academic, industrial, and professional engineering audience.

Introduction: Magnetic Hysteresis. Types of Hysteresis. Maxwells Equations and Thermodynamics: Maxwells Equations in Magnetic Media. Magnetic Work and Thermodynamics. Magnetic Free Energy: Exchange and Anisotropy. Micromagnetics. Magnetic Domains and Domain Walls. The Magnetization Process: Coherent Rotation. Domain Wall Motion. Magnetization Curves. Coercivity Mechanisms. Eddy Currents. Preisach Systems: Collections of Bistable Units. Hysteresis in Preisach Systems. Appendixes: Systems of Units. Vector Relations. Reciprocity Theorems. Micromagnetic Parameters. Stochastic Processes. Bibliography. Index.