The magnetic stability of two different interracial exchange coupled systems are investigated using the magneto-optic Kerr effect during repeated reversal of the soft layer magnetization by field cycling up to 107 times. For Fe/Cr double-superlattice exchange biased systems, small but rapid initial decay of exchange bias field H{sub E} and the remanent magnetization is observed. Also the Sin-Co/Fe bilayers grown epitaxially with uniaxial in-plane anisotropy show similar decay. However, the H{sub E} of biaxial and random in-plane bilayers, shows gradual decay without large reduction of the magnetization. These different decay behaviors explained by their different microstructure and interracial spin configurations.

We have studied the magnetic stability in exchange bias and exchange spring systems prepared via epitaxial sputter deposition. The two interfacial exchange coupled systems, Fe/Cr(211) double superlattices consisting of a ferromagnetic and an antiferromagnetic Fe/Cr superlattice that are exchange coupled through a Cr spacer, and Sin-Co/Fe exchange-spring bilayer structures with ferromagnetically coupled hard Sin-Co layer and soft Fe layer, were epitaxially grown on suitably prepared Cr buffer layers to give rise to different microstructure and magnetic anisotropy. The magnetic stability was investigated using the magneto-optic Kerr effect during repeated reversal of the soft layer magnetization by field cycling up to 107 times. For uniaxial Fe/Cr exchange biased double superlattices and exchange spring bilayers with uniaxial Sin-Co, small but rapid initial decay in the exchange bias field HE and in the remanent magnetization is observed. However, the exchange spring bilayers with biaxial and random in-plane anisotropy in the Sin-Co layer shows gradual decay in H{sub E} and without large reduction of the magnetization. The different decay behaviors are attributed to the different microstructure and spin configuration of the pinning layers.

The area of magnetic interactions in solids has been of technical importance and academic interest for several decades. The concept of superexchange was introduced in solid state physics in order to correlate observed magnetic behavior with electronic and crystal structure in simple inorganic systems like ferrites. These ideas were usually cast in terms of valence bond arguments and applied to high synmetry situations. In the past decade, inorganic chemists have been active in the characterization of the magnetic behavior of a wide range of transition metal polymers and clusters. In a few instances, it has been possible to deduce simple magnetic-structural correla tions for structural changes involving variation of a structural parameter over a rather limited range. Simul taneously, superexchange arguments have been recast in the language of chemistry and have provided the basis for the interpretation of these correlations on a molecular level. However, as of yet, the range of successful application of these principles has been quite limited. Thus, there was a timely need to bring together the people active in this area to discuss approaches and ideas that can help bring this area of research to maturity.

This thesis presents recent developments in magnetic coupling phenomena of ferrimagnetic rare-earth transition-metal Tb-Fe alloys and coupled systems consisting of ferri-/ferromagnetic heterostructures. Taking advantage of the tunability of the exchange coupling between ferrimagnetic and ferromagnetic layers by means of stoichiometry of the Tb-Fe layer, the variable number of repetitions in the Co/Pt multilayer as well as the thickness of an interlayer spacer, it is demonstrated that large perpendicular unidirectional anisotropy can be induced at room temperature. This robust perpendicular exchange bias at room temperature opens up a path towards applications in spintronics.

Novel Magnetic Nanostructures: Unique Properties and Applications reviews the synthesis, design, characterization and unique properties of emerging nanostructured magnetic materials. It discusses the most promising and relevant applications, including data storage, spintronics and biomedical applications. Properties investigated include electronic, self-assembling, multifunctional, and magnetic properties, along with magnetic phenomena. Structures range from magnetic nanoclusters, nanoparticles, and nanowires, to multilayers and self-assembling nanosystems. This book provides a better understanding of the static and dynamic magnetism in new nanostructures for important applications. - Provides an overview of the latest research on novel magnetic nanostructures, including molecular nanomagnets, metallacrown magnetic nanostructures, magnetic dendrimers, self-assembling magnetic structures, multifunctional nanostructures, and much more - Reviews the synthesis, design, characterization and detection of useful properties in new magnetic nanostructures - Highlights the most relevant applications, including spintronic, data storage and biomedical applications

This book is intended to collect in one place as much information as possible on the use of EPR spectroscopy in the analysis of systems in which two or more spins are magnetically coupled. This is a field where research is very active and chemists are elbow-to-elbow with physicists and biologists in the forefront. Here, as in many other fields, the contributions coming from different disciplines are very important, but for active researchers it is sometimes difficult to follow the literature, due to differences in languages, and sources which are familiar to, e. g. , a physicist, are exotic to a chemist. Therefore, an effort is needed in order to provide a unitary description of the many different phenomena which are collected under the title. In order to define the arguments which are treated, it is useful to state clearly what is not contained here. So we do not treat magnetic phenomena in conductors and we neglect ferro- and antiferromagnetic resonance. The basic foundations of EPR spectroscopy are supposed to be known by the reader, while we introduce the basis of magnetic interactions between spins. In the first two chapters we review the foundations of exchange interactions, trying to show how the magnetic parameters are bound to the electronic structure of the interacting centers.

The expert authors of this monograph and professional reference include Dante Gatteschi, a pioneer of molecular magnetism. Based on the spin Hamiltonian approach, this unified treatment makes extensive use of irreducible tensor techniques to analyze systems in which two or more spins are magnetically coupled. 177 figures, 38 tables, and a new Introduction by Dr. Gatteschi. 1990 edition.