This book provides a state-of-the art overview of a highly interesting emerging research field in solid state physics/nanomaterials science, topological structures in ferroic materials. Topological structures in ferroic materials have received strongly increasing attention in the last few years. Such structures include domain walls, skyrmions and vortices, which can form in ferroelectric, magnetic, ferroelastic or multiferroic materials. These topological structures can have completely different properties from the bulk material they form in. They also can be controlled by external fields (electrical, magnetic, strain) or currents, which makes them interesting from a fundamental research point of view as well as for potential novel nanomaterials applications. To provide a comprehensive overview, international leading researches in these fields contributed review-like chapters about their own work and the work of other researchers to provide a current view of this highly interesting topic.

"a very detailed book on multiferroics that will be useful for PhD students and researchers interested in this emerging field of materials science" —Dr. Wilfrid Prellier, Research Director, CNRS, Caen, France Multiferroics has emerged as one of the hottest topics in solid state physics in this millennium. The coexistence of multiple ferroic/antiferroic properties makes them useful both for fundamental studies and practical applications such as revolutionary new memory technologies and next-generation spintronics devices. This book provides an historical introduction to the field, followed by a summary of recent progress in single-phase multiferroics (type-I and type-II), multiferroic composites (bulk and nano composites), and emerging areas such as domain walls and vortices. Each chapter addresses potential technological implications. There is also a section dedicated to theoretical approaches, both phenomenological and first-principles calculations.

Multiferroics, materials with a coexistence of magnetic and ferroelectric order, provide an efficient route for the control of magnetism by electric fields. The authors cover multiferroic thin-film heterostructures, device architectures and domain/interface effects. They critically discuss achievements as well as limitations and assess opportunities for future applications.

Magnetic skyrmions are particle-like objects described by localized solutions of non-linear partial differential equations. Up until a few decades ago, it was believed that magnetic skyrmions only existed in condensed matter as short-term excitations that would quickly collapse into linear singularities. The contrary was proven theoretically in 1989 and evidentially in 2009. It is now known that skyrmions can exist as long-living metastable configurations in low-symmetry condensed matter systems with broken mirror symmetry, increasing the potential applications possible. Magnetic Skyrmions and their Applications delves into the fundamental principles and most recent research and developments surrounding these unique magnetic particles. Despite achievements in the synthesis of systems stabilizing chiral magnetic skyrmions and the variety of experimental investigations and numerical calculations, there have not been many summaries of the fundamental physical principles governing magnetic skyrmions or integrating those concepts with methods of detection, characterization and potential applications. Magnetic Skyrmions and their Applications delivers a coherent, state-of-the-art discussion on the current knowledge and potential applications of magnetic skyrmions in magnetic materials and device applications. First the book reviews key concepts such as topology, magnetism and materials for magnetic skyrmions. Then, charactization methods, physical mechanisms, and emerging applications are discussed. - Covers background knowledge and details the basic principles of magnetic skyrmions, including materials, characterization, statics and dynamics - Reviews materials for skyrmion stabilization including bulk materials and interface-dominated multilayer materials - Describes both well-known and unconventional applications of magnetic skyrmions, such as memristors and reservoir computing

This book is dedicated to modeling and application of magnetoelectric (ME) effects in layered and bulk composites based on magnetostrictive and piezoelectric materials. Currently, numerous theoretical and experimental studies on ME composites are available but few on the development and research of instruments based on them. So far, only investigation of ME magnetic field sensors has been cited in the existing literature. However, these studies have finally resulted in the creation of low-frequency ME magnetic field sensors with parameters substantially exceeding the characteristics of Hall sensors. The book presents the authors’ many years of experience gained in ME composites and through creation of device models based on their studies. It describes low-frequency ME devices, such as current and position sensors and energy harvesters, and microwave ME devices, such as antennas, attenuators, filters, gyrators, and phase shifters.

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.

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.