The energy cost associated with modern information technologies has been increasing exponentially over time, stimulating the search for alternative information storage and processing devices. Magnetic skyrmions are solitonic nanometer-scale quasiparticles whose unique topological properties can be thought of as that of a Mobius strip. Skyrmions are envisioned as information carriers in novel information processing and storage devices with low power consumption and high information density. As such, they could contribute to solving the energy challenge. In order to be used in applications, isolated skyrmions must be thermally stable at the scale of years. In this work, their stability is studied through two main approaches: the Kramers' method in the form of Langer's theory, and the forward flux sampling method. Good agreement is found between the two methods. We find that small skyrmions possess low internal energy barriers, but are stabilized by a large activation entropy. This is a direct consequence of the existence of stable modes of deformation of the skyrmion. Additionally, frustrated exchange that arises at some transition metal interfaces leads to new collapse paths in the form of the partial nucleation of the corresponding antiparticle, as merons and antimerons.

The Symposium on Magnetic Ultrathin Films, Multilayers and Surfaces, hosted by the European Materials Research Society, was held at the Palais de la Musique et des Congré in Strasbourg, France on June 4-7, 1996. Its central theme was the relationship of magnetic properties and device performance to structure at the nano and micrometer length scale. Research on the magnetism of surfaces, ultrathin films and multilayers has increased dramatically during recent years. This development was triggered by the discovery of coupling between ferromagnetic layers across nonmagnetic spacer layers and of the giant magnetoresistance effect in systems of reduced dimension using various micro and nanofabrication techniques has become a subject of special interest. It is certainly the promising application potential of these effects in new magnetic recording device geometries which causes this intensive research, which is done both by companies and at universities and research institutes. A selection of invited and contributed papers presented at the Symposium and accepted for publication is contained in this volume. The contents of these proceedings are organized into seven sections. A. Nanowires, Nanoparticles, Nanostructuring B. Ultrathin Films and Surfaces, Characterization C. Giant Magnetoresistance D. Coupling, Tunneling E. Growth, Structure, Magnetism F. Growth, Structure, Magnetoresistance G. Coupling, Magnetic processes, Magneto-optics. The first four sections contain invited and oral contributed papers in the listed research domains, while the last three sections contain the contributions presented during three large poster sessions.

This book contains the proceedings of 3 symposia dealing with various aspects of small scale structures. Symposium A deals with the development of new materials, including ceramics, polymers, metals, etc., their microstructuring as well as their potential for application in microsystems. All kinds of microsystems are considered, e.g. mechanical, magnetic, optical, chemical, biochemical and issues related to assembly and packaging were also covered.Symposium B deals with four topics: synthesis and preparation of nanostructured ceramics and composites with well-controlled geometric order and chemical composition; coupling of these structures to transducers for current and future chemical and biochemical devices based upon microoptics, microelectronics, microionics, microelectrodes or molecular cages; planar thin film structures and the control of covalent thin film/transducer couplings, the control of selective, stable and sensitive recognition centers at the surface, at grain boundaries or in the bulk of selected nanostructured materials with extremely narrow particle size distributions; analysis of these structures and sensor functions by means of techniques utilizing photons, electrons, ions, or atomic particle beam probes.Symposium E examines the structure-property relationships in thin films and multilayers, from the point of view of both fundamental studies and practical applications.

Nanoscience is of central importance in the physical and biological sciences and is now pervasive in technology. However nanomagnetism has a special role to play as magnetic properties depend uniquely on both dimensionality and lengthscales. Nanomagnetism is already central to data storage, sensor and device technologies but is increasingly being used in the life sciences and medicine. This volume aims to introduce scientists, computer scientists, engineers and technologists from diverse fields to this fascinating and technologically important new branch of nanoscience. The volume should appeal to both the interested general reader but also to the researcher wishing to obtain an overview of this fast moving field. The contributions come from acknowledged leaders in the field who each give authoritative accounts of key fundamental aspects of nanomagnetism to which they have themselves made a major contribution. After a brief introduction by the editors, Wu first surveys the fundamental properties of magnetic nanostructures. The interlayer exchange interactions within magnetic multilayer structures is next discussed by Stiles. Camley then discusses the static, dynamic and thermal properties of magnetic multilayers and nanostructures, followed by an account of the phenomenon of exchange anisotropy by Berkowitz and Kodama. This latter phenomenon is widely in current read head devices for example. The transport properties of nanostructures also are spectacular, and again underpin computer technology, as we see from the discussion of giant magnetoresistance (GMR) and tunnelling magnetoresistance (TMR) presented by Fert and his colleagues. Beyond GMR and TMR we look to the field of spintronics where new electronic devices are envisioned and for which quantumcomputing may depend as discussed in the chapter by Flatte and Jonker.The volume concludes with discussion of the recently discovered phenomenon of current induced switching of magnetization by Edwards and Mathon.* Subject is in the forefront of nanoscience* All Section authors are leading figures in this key field* Presentations are accessible to non specialists, with focus on underlying fundamentals

The ability to understand and control the unique properties of interfaces has created an entirely new field of magnetism, with profound impact in technology and serving as the basis for a revolution in electronics. Our understanding of the physics of magnetic nanostructures has also advanced significantly. This rapid development has generated a need for a comprehensive treatment that can serve as an introduction to the field for those entering it from diverse fields, but which will also serve as a timely overview for those already working in this area. The four-volume work Ultra-Thin Magnetic Structures aims to fulfill this dual need. The original two volumes – now available once more – are "An Introduction to the Electronic, Magnetic and Structural Properties" (Vol. I) and Measurement Techniques and Novel Magnetic Properties (this volume). Two new volumes, "Fundamentals of Nanomagnetism" and "Applications of Nanomagnetism," extend and complete this comprehensive work by presenting the foundations of spintronics.

Materials Research in thin and ultrathin magnetic structures is a multidisciplinary field which heavily relies on state-of-the-art growth, characterization and theoretical approaches to build a comprehensive physical picture on how magnetic properties depend on interfacial structural issues, interlayer coupling and transport phenomena. Often in this field, the critical properties and characterization required necessitates knowledge of structural and magnetic phenomena extending over several atomic planes. Atomic controlled growth techniques are required and atomic sensitivity is needed from magnetic and structural probes. This critical knowledge is vital for device applications, providing the basis for the synergistic interactions that are predominant in this field of research. This volume is the definitive reference source for anyone interested in the latest advances and results of current experimental research in ultrathin film magnetism.

The ability to understand and control the unique properties of interfaces has created an entirely new field of magnetism, with profound impact in technology and serving as the basis for a revolution in electronics. Our understanding of the physics of magnetic nanostructures has also advanced significantly. This rapid development has generated a need for a comprehensive treatment that can serve as an introduction to the field for those entering it from diverse fields, but which will also serve as a timely overview for those already working in this area. The four-volume work Ultra-Thin Magnetic Structures aims to fulfill this dual need. The original two volumes – now available once more – are An Introduction to the Electronic, Magnetic and Structural Properties (this volume) and "Measurement Techniques and Novel Magnetic Properties." Two new volumes, "Fundamentals of Nanomagnetism" and "Applications of Nanomagnetism," extend and complete this comprehensive work by presenting the foundations of spintronics.