Ballistic Electron Magnetic Microscopy
Author: William Horrocks Rippard
Publisher:
Published: 2001
Total Pages: 664
ISBN-13:
DOWNLOAD EBOOK →Author: William Horrocks Rippard
Publisher:
Published: 2001
Total Pages: 664
ISBN-13:
DOWNLOAD EBOOK →Author: William Horrocks Rippard
Publisher:
Published: 2001
Total Pages: 312
ISBN-13: 9780599957060
DOWNLOAD EBOOK →Electron transport through thin AlOx based magnetic tunnel junctions has also been studied at the nanometer length scale. The effective barrier height of these insulating barriers has been determined to be 1.25 +/- 0.5 eV. The transmission probability of hot electrons through these barriers has also been measured. Tunnel junctions prepared by thermal evaporation and sputter deposition are compared. While the effective barrier height of junctions formed by the two techniques are very similar, the electron transmission probabilities through the two types of barriers are different.
Author: Yann Claveau
Publisher:
Published: 2014
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOK →After the discovery of Giant Magneto-Resistance (GMR) by Albert Fert and Peter Grünberg, electronics had a breakthrough with the birth of a new branch called spintronics. This discipline, while still young, exploit the spin of electrons, for instance to store digital information. Most quantum devices exploiting this property of electrons consist of alternating magnetic and nonmagnetic thin layers on a semiconductor substrate. One of the best tools used for characterizing these structures, invented in 1988 by Kaiser and Bell, is the so-called Ballistic Electron Emission Microscope (BEEM). Originally, this microscope, derived from the scanning tunneling microscope (STM), was dedicated to the imaging of buried (nanometer-scale) objects and to the study of the potential barrier (Schottky barrier) formed at the interface of a metal and a semiconductor when placed in contact. With the development of spintronics, the BEEM became an essential spectroscopy technique but still fundamentally misunderstood. It was in 1996 that the first realistic model, based on the non-equilibrium Keldysh formalism, was proposed to describe the transport of electrons during BEEM experiments. In particular, this model allowed to explain some experimental results previously misunderstood. However, despite its success, its use was limited to the study of semi-infinite structures through a calculation method called decimation of Green functions. In this context, we have extended this model to the case of thin films and hetero-structures like spin valves: starting from the same postulate that electrons follow the band structure of materials in which they propagate, we have established an iterative formula allowing calculation of the Green functions of the finite system by tight-binding method. This calculation of Green's functions has been encoded in a FORTRAN 90 program, BEEM v3, in order to calculate the BEEM current and the surface density of states. In parallel, we have developed a simpler method which allows to avoid passing through the non-equilibrium Keldysh formalism. Despite its simplicity, we have shown that this intuitive approach gives some physical interpretation qualitatively similar to the non-equilibrium approach. However, for a more detailed study, the use of “non-equilibrium approach” is inevitable, especially for the detection of thickness effects linked to layer interfaces. We hope these both tools should be useful to experimentalists, especially for the Surfaces and Interfaces team of our department.
Author: S. Amelinckx
Publisher: John Wiley & Sons
Published: 2008-08-29
Total Pages: 507
ISBN-13: 3527620532
DOWNLOAD EBOOK →Comprehensive in coverage, written and edited by leading experts in the field, this Handbook is a definitive, up-to-date reference work. The Volumes Methods I and Methods II detail the physico-chemical basis and capabilities of the various microscopy techniques used in materials science. The Volume Applications illustrates the results obtained by all available methods for the main classes of materials, showing which technique can be successfully applied to a given material in order to obtain the desired information. With the Handbook of Microscopy, scientists and engineers involved in materials characterization will be in a position to answer two key questions: "How does a given technique work?", and "Which techique is suitable for characterizing a given material?"
Author: Damien Alloyeau
Publisher: Springer Science & Business Media
Published: 2012-07-13
Total Pages: 415
ISBN-13: 1447140141
DOWNLOAD EBOOK →Bimetallic nanoparticles, also called nanoalloys, are at the heart of nanoscience because of their ability to tune together composition and size for specific purposes. By approaching both their physical and chemical properties, Nanoalloys: Synthesis, Structure & Properties provides a comprehensive reference to this research field in nanoscience by addressing the subject from both experimental and theoretical points of view, providing chapters across three main topics: Growth and structural properties Thermodynamics and electronic structure of nanoalloys Magnetic, optic and catalytic properties The growth and elaboration processes which are the necessary and crucial part of any experimental approach are detailed in the first chapter. Three chapters are focused on the widely used characterization techniques sensitive to both the structural arrangements and chemistry of nanoalloys. The electronic structure of nanoalloys is described as a guide of useful concepts and theoretical tools. Chapters covering thermodynamics begin with bulk alloys, going to nanoalloys via surfaces in order to describe chemical order/disorder, segregation and phase transitions in reduced dimension. Finally, the optical, magnetic and catalytic properties are discussed by focusing on nanoparticles formed with one element to track the modifications which occur when forming nanoalloys. The range and detail of Nanoalloys: Synthesis, Structure & Properties makes it an ideal resource for postgraduates and researchers working in the field of nanoscience looking to expand and support their knowledge of nanoalloys.
Author: Yimei Zhu
Publisher: Springer Science & Business Media
Published: 2005-12-06
Total Pages: 628
ISBN-13: 0387233954
DOWNLOAD EBOOK →Modern Techniques for Characterizing Magnetic Materials provides an extensive overview of novel characterization tools for magnetic materials including neutron, photon and electron scatterings and other microscopy techniques by world-renowned scientists. This interdisciplinary reference describes all available techniques to characterize and to understand magnetic materials, techniques that cover a wide range of length scales and belong to different scientific communities. The diverse contributions enhance cross-discipline communication, while also identifying both the drawbacks and advantages of different techniques, which can result in deriving effective combinations of techniques that are especially fruitful at nanometer scales. It will be a valuable resource for all graduate students, researchers, engineers and scientists who are interested in magnetic materials including their crystal structure, electronic structure, magnetization dynamics and their associated magnetic properties and underlying magnetism.
Author: Gianluca Gubbiotti
Publisher: CRC Press
Published: 2019-07-10
Total Pages: 264
ISBN-13: 1000024547
DOWNLOAD EBOOK →Magnonics, a research field that uses spin waves, collective excitations of ordered magnetic materials, or magnons (their quanta) as a tool for signal processing, communication, and computation, has rapidly grown during the past decade because of the low-energy consumption and potential compatibility with next-generation circuits beyond CMOS electronics. The interest in 3D magnonic nanostructures follows the latest trend in conventional electronics based on expansion from 2D planar to 3D vertically integrated structures. To remain on the same technological level, a similar expansion should be realized in magnonics. Following this trend, this book provides an overview of recent developments in the exploitation of the third dimension in magnonics, with special focus on the propagation of spin waves in layered magnonic crystals, spin textures, curved surfaces, 3D nano-objects, and cavity magnonics.
Author: Burkard Hillebrands
Publisher: Springer Science & Business Media
Published: 2001-11-06
Total Pages: 363
ISBN-13: 3540411917
DOWNLOAD EBOOK →Introductory chapters help newcomers to understand the basic concepts, and the more advanced chapters give the current state of the art for most spin dynamic issues in the milliseconds to femtoseconds range. Emphasis is placed on both the discussion of the experimental techniques and on the theoretical work. The comprehensive presentation of these developments makes this volume very timely and valuable for every researcher working in the field of magnetism.
Author: David D. Awschalom
Publisher: Springer Science & Business Media
Published: 2013-06-29
Total Pages: 216
ISBN-13: 9401705321
DOWNLOAD EBOOK →The history of scientific research and technological development is replete with examples of breakthroughs that have advanced the frontiers of knowledge, but seldom does it record events that constitute paradigm shifts in broad areas of intellectual pursuit. One notable exception, however, is that of spin electronics (also called spintronics, magnetoelectronics or magnetronics), wherein information is carried by electron spin in addition to, or in place of, electron charge. It is now well established in scientific and engineering communities that Moore's Law, having been an excellent predictor of integrated circuit density and computer performance since the 1970s, now faces great challenges as the scale of electronic devices has been reduced to the level where quantum effects become significant factors in device operation. Electron spin is one such effect that offers the opportunity to continue the gains predicted by Moore's Law, by taking advantage of the confluence of magnetics and semiconductor electronics in the newly emerging discipline of spin electronics. From a fundamental viewpoine, spin-polarization transport in a material occurs when there is an imbalance of spin populations at the Fermi energy. In ferromagnetic metals this imbalance results from a shift in the energy states available to spin-up and spin-down electrons. In practical applications, a ferromagnetic metal may be used as a source of spin-polarized electronics to be injected into a semiconductor, a superconductor or a normal metal, or to tunnel through an insulating barrier.