Hard X Ray Photoelectron Spectroscopy Of Deeply Buried Magnetic Layers

This work focuses on the investigation of multilayer structures, employed in spintronics devices, by a number of techniques based on hard x-ray photoelectron spectroscopy (HAXPES). The application of hard x-rays increases the inelastic mean free path of the emitted electrons what makes HAXPES a non-destructive bulk sensitive probe for solid state research, especially studies of buried layers. Magnetoelectronic properties such as exchange splitting in ferromagnetic materials as well as the macroscopic magnetic ordering can be studied by magnetic circular dichroism in photoemission (MCDAD). In the present work MCDAD was integrated into HAXPES to explore the magnetic phenomena in deeply buried layers of the complex multilayer structures. In turn, direct measurements of electron spins of ferromagnets always attracted much attention but up to date have been limited by the surface sensitivity of the developed techniques. The last part of the work presents the results of the successfully performed spin-resolved HAXPES experiment using a spin polarimeter of the SPLEED-type on a buried magnetic layer.

Spintronics is an emerging technology exploiting the spin degree of freedom and has proved to be very promising for new types of fast electronic devices. Amongst the anticipated advantages of spintronics technologies, researchers have identified the non-volatile storage of data with high density and low energy consumption as particularly relevant. This monograph examines the concept of half-metallic compounds perspectives to obtain novel solutions and discusses several oxides such as perovskites, double perovskites and CrO2 as well as Heusler compounds. Such materials can be designed and made with high spin polarization and, especially in the case of Heusler compounds, many material-related problems present in current-day 3d metal systems, can be overcome. Spintronics: From Materials to Devices provides an insight into the current research on Heusler compounds and offers a general understanding of structure–property relationships, including the influence of disorder and correlations on the electronic structure and interfaces. Spintronics devices such as magnetic tunnel junctions (MTJs) and giant magnetoresistance (GMR) devices, with current perpendicular to the plane, in which Co2 based Heusler compounds are used as new electrode materials, are also introduced. From materials design by theoretical methods and the preparation and properties of the materials to the production of thin films and devices, this monograph represents a valuable guide to both novices and experts in the fields of Chemistry, Physics, and Materials Science.

This book provides the first complete and up-to-date summary of the state of the art in HAXPES and motivates readers to harness its powerful capabilities in their own research. The chapters are written by experts. They include historical work, modern instrumentation, theory and applications. This book spans from physics to chemistry and materials science and engineering. In consideration of the rapid development of the technique, several chapters include highlights illustrating future opportunities as well.

Photoemission spectroscopy is one of the most extensively used methods to study the electronic structure of atoms, molecules, and solids and their surfaces. This volume introduces and surveys the field at highest energy and momentum resolutions allowing for a new range of applications, in particular for studies of high temperature superconductors.

This book summarizes the most recent and compelling experimental results for complex oxide interfaces. The results of this book were obtained with the cutting-edge photoemission technique at highest energy resolution. Due to their fascinating properties for new-generation electronic devices and the challenge of investigating buried regions, the book chiefly focuses on complex oxide interfaces. The crucial feature of exploring buried interfaces is the use of soft X-ray angle-resolved photoemission spectroscopy (ARPES) operating on the energy range of a few hundred eV to increase the photoelectron mean free path, enabling the photons to penetrate through the top layers – in contrast to conventional ultraviolet (UV)-ARPES techniques. The results presented here, achieved by different research groups around the world, are summarized in a clearly structured way and discussed in comparison with other photoemission spectroscopy techniques and other oxide materials. They are complemented and supported by the most recent theoretical calculations as well as results of complementary experimental techniques including electron transport and inelastic resonant X-ray scattering.

This book concisely illustrates the techniques of major surface analysis and their applications to a few key examples. Surfaces play crucial roles in various interfacial processes, and their electronic/geometric structures rule the physical/chemical properties. In the last several decades, various techniques for surface analysis have been developed in conjunction with advances in optics, electronics, and quantum beams. This book provides a useful resource for a wide range of scientists and engineers from students to professionals in understanding the main points of each technique, such as principles, capabilities and requirements, at a glance. It is a contemporary encyclopedia for selecting the appropriate method depending on the reader's purpose.