Download or read book Influence of Electronic Structure on the Magnetic Properties of IV VI Diluted Magnetic Semiconductors written by and published by . This book was released on 2001 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigated the magnetic and thermal properties of chalcogenide-based diluted magnetic semiconductor (DMS) systems. These systems have been considered as possible novel materials with increased magnetic sensitivity and thermoelectric efficiency. Measurements of the magnetic properties of Sn(1-x)Gd(x)Te show that there is an antiferromagnetic pair-exchange interaction with a maximum in the magnitude at a hole concentration of about 3 x 10(exp 20) /cu cm. The interpretation of this result is based on the relative positions of the Gd 5d level, the Fermi level, and the L and sum sigma levels in the valence band. We have also measured the low-temperature specific heat in these DMS systems. Theoretical calculations have shown that one must take into account the systems of magnetic ions and the carriers and the interactions between them in order to obtain an approximate fit to the data. We have performed measurements of the thermoelectric power, thermoelectric figure of merit, and electrical conductivity in P(1-x)Mn(x)Te. The thermoelectric power increased as the Mn-content increased, but a decrease in the carrier mobility limited the thermoelectric figure of merit. In new quaternary and pentenary DMS we have observed a paramagnet - ferromagnet transition and a temperature dependent anomalous Hall effect.

Download or read book Diluted Magnetic Semiconductors written by Mukesh Jain and published by World Scientific. This book was released on 1991-10-31 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: This review volume presents both basic and applied aspects of diluted magnetic semiconductors (DMS). The term DMS applies generally to semiconductors in which a fraction of its constituent ions are replaced by magnetic ions. This book is only the second to review DMS materials. It presents a detailed treatment of the current state of knowledge of the established properties of DMS in the form of single crystals, quantum wells and superlattices. It also brings together recent work on new DMS materials and presents discussions on a wide range of possible DMS applications.

Download or read book Handbook of Spintronic Semiconductors written by Weimin Chen and published by CRC Press. This book was released on 2019-05-08 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an in-depth review of the rapidly developing field of spintronic semiconductors. It covers a broad range of topics, including growth and basic physical properties of diluted magnetic semiconductors based on II-VI, III-V and IV semiconductors, recent developments in theory and experimental techniques and potential device applications; its aim is to provide postgraduate students, researchers and engineers a comprehensive overview of our present knowledge and future perspectives of spintronic semiconductors.

Download or read book First Principle Vs Experimental Design of Diluted Magnetic Semiconductors written by Omar Mounkachi and published by Nova Science Publishers. This book was released on 2018-10 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent discoveries have given rise to a new class of electronics known as "spin electronics or spintronics," which uses the electron spin rather than its charge to create polarized currents. Spintronics is currently experiencing an extraordinary development with the manufacture of nanoscale devices based on ferromagnetic materials and semiconductors. Their applications are numerous, ranging from recording, electronics, and optoelectronics to quantum information. Spintronics is a new generation of electronics that has brought and continues to bring a lot of progress to information storage; this is due to the discovery of new materials with new functionalities and multiple applications. The discovery of giant magnetoresistance (GMR) in 1988 by Albert Fert and Peter Grünberg (receiver of the Nobel Prize in Physics in 2007) is considered a starting point of spintronics. GMR is based on the variation of the electric current in the presence of a magnetic field. The spintronics has made important contributions to the miniaturization desired for electronics; it uses nanometric components for processing and storing information. However, the limits of miniaturization on a nanometric scale are known, and it is imperative to develop new ways and new materials to exceed those limits. The most desired properties for these materials are high spin polarization, modular magnetic properties by an electric field and a long lifetime of the spin polarization. Among the new promising materials, we cite the following: Diluted magnetic semiconductors, which give new magnetic properties of conventional semiconductors, functional oxides (including the semi-metals and multiferroic metals) and organic semiconductors. The main theoretical challenge in this area is to understand how the macroscopic magnetic behavior observed results from interactions of a large number of degrees of microscopic freedom. In these systems the disorder is an essential parameter of magnetic phenomena, and due to random locations of impurity atoms it can lead to a total physical difference from the observed absence. There has been considerable recent advances in the design of these materials as diluted magnetic semiconductors (DMS, or diluted magnetic semiconductors), and a number of semiconductors were investigated as II-VI group and III-V group doped compounds, with transition metals substituting their original cations. There are several different theoretical approaches to study these magnetic materials. The ab-initio approach starts from the Schrödinger equation to simulate a given material. Such an approach is essential to determine the parameters and microscopic properties of such a system. In this book, the authors analyzed the electronic structure of magnetic semiconductors diluted in the case of ZnO, GaN, SnO2, TiO2, MgH2, EuO and EuN doped RENs (RE=GdN, DyN and HoN). The authors focused on magnetic, optical and exchange mechanisms which control the ferromagnetism in these systems. The purpose of this book is to propose some ideas to answer the most important question in material science for semiconductor spintronics, primarily considering how room-temperature ferromagnetism in DMS can be realized. Additionally, the correlation between first principle and experimental design to see how properties of yet-to-be-synthesized materials can be predicted is discussed.

Download or read book Diluted Magnetic Semiconductors written by Mukesh Kumar Jain and published by World Scientific. This book was released on 1991 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt: This review volume presents both basic and applied aspects of diluted magnetic semiconductors (DMS). The term DMS applies generally to semiconductors in which a fraction of its constituent ions are replaced by magnetic ions. This book is only the second to review DMS materials. It presents a detailed treatment of the current state of knowledge of the established properties of DMS in the form of single crystals, quantum wells and superlattices. It also brings together recent work on new DMS materials and presents discussions on a wide range of possible DMS applications.

Download or read book Magnetization Dynamics in Diluted Magnetic Semiconductor Heterostructures written by Martin Kneip and published by GRIN Verlag. This book was released on 2009-02-17 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral Thesis / Dissertation from the year 2008 in the subject Physics - Theoretical Physics, grade: sehr gut (1,0), University of Dortmund, language: English, abstract: In this thesis spin dynamics in (Zn,Mn)Se/(Zn,Be)Se and (Cd,Mn)Te/(Cd,Mg)Te DMS quantum well heterostructures with a type-I band alignment are studied, where the carriers are quantum confined. Especially the important role of free carriers in heating of the Mn-system, by its interaction with photoexcited carriers with excess kinetic energy, and in the cooling of the Mn-system in the presence of cold background carriers, provided by modulation doping, is established. The studies are separated in three chapters. In the fourth chapter of this thesis, new results on energy and spin transfer between free carriers and Mn-ion system are presented. Contributions of direct heating of the Mn-system by photocarriers and indirect heating via nonequilibrium phonons are distinguished and their competition is discussed. In the fifth chapter dynamics of spin-lattice relaxation of magnetic Mn-ions in DMS QW heterostructures is investigated and new experimental studies on (Zn,Mn)Se/(Zn,Be)Se heterostructures are shown. Crucial for spintronic devices is the ability to tune the spin relaxation time precisely, as the spin relaxation time is important in double respects. On the one hand spin polarization must be conserved over long times and distances, if the spin shall be processed or stored in a region, which is spatial separated from the spin-injector. Especially for the possibility of utilizing spins as quantum bits for quantum information processing, long spin polarization is needed. On the other hand short spin relaxation time is needed for fast switching between different spin-states. For instance semiconductor lasers can be switched off extremely fast by reorientation of spin. This very relevant topic is devoted the sixth chapter, before the thesis is summarized in the last chapter. Especially for one of the biggest drawbacks for precise tuning, that the magnetization dynamics in DMS cannot be controlled separately from the static magnetization, solutions via electric field control of the magnetization dynamics or via the technological concept of “digital alloying” are presented.precise tuning, that the magnetization dynamics in DMS cannot be controlled separately from the static magnetization, solutions via electric field control of the magnetization dynamics or via the technological concept of “digital alloying” are presented.

Download or read book Semimagnetic Semiconductors and Diluted Magnetic Semiconductors written by M. Averous and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semimagnetic semiconductors (SMSC) and diluted magnetic semiconductors (DMS) have in the past decade attracted considerable attention because they confer many new physical properties on both bulk materials and heterostructures. These new effects are due either to exchange interactions between magnetic moments on magnetic ions, or to exchange interactions between magnetic moments and the spin of the charge carrier. These effects vary with the transition metal (Mn, Fe, Co) or rare earth (Eu, Gd, etc) used and thus provide a range of different situations. The field is very large (zero gap, small gap, wide gap), and the magnetic properties also are very rich (paramagnetic spin glass, antiferromagnetism). These materials are very convenient for studying the magnetism (the magnetism is diluted) or the superlattices (SL) with a continuous change from type II SL to type III SL. This Course attempted to provide a complete overview of the topic. The participants of this summer school held in Erice came from ten countries and were from various backgrounds and included theoreticians, experimentalists, physicists, and chemists. Consequently, an attempt was made to make the Course as thorough as possible, but at the same time attention was devoted to basic principles. The lecturers, drawn from all the groups in the world involved in the field, were asked to be very didactic in their presentation. After two introductory lectures, Dr.

Download or read book Introduction to the Physics of Diluted Magnetic Semiconductors written by Jan A. Gaj and published by Springer Science & Business Media. This book was released on 2011-01-12 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: As materials whose semiconducting properties are influenced by magnetic ions, DMSs are central to the emerging field of spintronics. This volume focuses both on basic physical mechanisms (e.g. carrier-ion and ion-ion interactions), and resulting phenomena.

Download or read book Transition Metals and Silicon written by Benjamin Geisler and published by Cuvillier Verlag. This book was released on 2015-03-12 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present, richly illustrated book takes the reader on a tour through the field of modern spintronics, discussing key aspects such as ferromagnetic thin films, dilute magnetic semiconductors, and magnetic tunnel junctions. It demonstrates different approaches to a detailed understanding of magnetism and materials properties on the atomic scale, as required by the ongoing miniaturization of electronics. Due to their technological relevance, the focus lies on silicon and different transition metals like chromium, manganese, and iron. Among others, the following questions are addressed from the viewpoint of state-of-the-art computational physics: Is the scanning tunneling microscope capable of resolving even complex film atomic structures? How can we use its spin-sensitive form to gain insight into interactions of magnetic impurities in bulk semiconductors? Why is chromium-doped silicon especially interesting? Does one need a Seebeck coefficient to obtain spincaloric properties ab initio?

Download or read book The Electronic Structure and Field Effects of an Organic Based Room Temperature Magnetic Semiconductor written by Derek M. Lincoln and published by . This book was released on 2007 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: The future of spin-electronics or "spintronics" lies in the development of viable magnetic semiconductors that can effectively operate at room temperature Vanadium tetracyanoethylene (V[TCNE]~2) is a magnetic semiconductor with an ordering temperature well above that of room. Its highly disordered structure has hampered a comprehensive description of the interactions between the V and TCNE sublattices that give rise to its magnetic and electrical properties. We report the results of high-resolution x-ray absorption (XAS) and magnetic circular dichrosim (MCD) studies probing the electronic structure of V[TCNE]~2 in an effort to elucidate the nature of these interactions. Included in this study are the first reports of gas phase neutral TCNE XAS spectra as well as the first reports of MCD spectra of the carbon and nitrogen absorption edges for the V[TCNE]~2 system. The vanadium spectrum reveals a spin split L3 and L2 spectrum that is qualitatively modeled for V(II) using crystal field multiplet (CFM) theory calculations except for a region of excess intensity on the high energy side of both the L3 and L2 absorption edges. We speculate that the origin of this excess intensity is vanadium present in valence states higher than V(II) and antibonding states from the hybridization of the V centers and TCNE. Despite the localized nature of the x-ray absorption process the C and N spectra of the TCNE suggest that we are probing molecular final states of TCNE from different sites rather atomically isolated states. In addition, the carbon and nitrogen absorption spectra reveal that this molecular orbital structure remains largely intact in going from the gas phase to the condensed phase in V[TCNE]~2.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Magnetic Materials written by K.H.J. Buschow and published by Elsevier. This book was released on 2012-01-25 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 20 of the Handbook of Magnetic Materials, as the preceding volumes, has a dual purpose. As a textbook it is intended to help those who wish to be introduced to a given topic in the field of magnetism without the need to read the vast amount of literature published. As a work of reference it is intended for scientists active in magnetism research. To this dual purpose, Volume 20 is composed of topical review articles written by leading authorities. In each of these articles an extensive description is given in graphical as well as in tabular form, much emphasis being placed on the discussion of the experimental material in the framework of physics, chemistry and material science. It provides readers with novel trends and achievements in magnetism. - Composed of topical review articles written by leading authorities - Intended to be of assistance to those who wish to be introduced to a given topic in the field of magnetism - As a work of reference it is intended for scientists active in magnetism research - Provide the readership with novel trends and achievements in magnetism

Download or read book Quantum Efficiency in Complex Systems written by Uli Wu rfel and published by Academic Press. This book was released on 2011 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Radiationless transfer of excitation energy is at the hear of many processes in quantum physics, chemistry and nanotechnology. Currently, the standard picture of an incoherent Förster resonant excitation transfer is being challenged by the experimental findings of a long-lived quantum mechanical coherence in biomolecular light harvesting complexes. The role of this in molecular aggregates is addressed in the first part of this volume. Utilizing some of the underlying principles to optimize nano scale devices, the second part addresses systems of colloid quantum dots and polymer based organic solar cells.

Download or read book 21st Century Nanoscience A Handbook written by Klaus D. Sattler and published by CRC Press. This book was released on 2020-11-09 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: 21st Century Nanoscience - A Handbook: Low-Dimensional Materials and Morphologies (Volume 4) will be the most comprehensive, up-to-date large reference work for the field of nanoscience. Handbook of Nanophysics by the same editor published in the fall of 2010 and was embraced as the first comprehensive reference to consider both fundamental and applied aspects of nanophysics. This follow-up project has been conceived as a necessary expansion and full update that considers the significant advances made in the field since 2010. It goes well beyond the physics as warranted by recent developments in the field. This fourth volume in a ten-volume set covers low-dimensional materials and morphologies. Key Features: Provides the most comprehensive, up-to-date large reference work for the field. Chapters written by international experts in the field. Emphasises presentation and real results and applications. This handbook distinguishes itself from other works by its breadth of coverage, readability and timely topics. The intended readership is very broad, from students and instructors to engineers, physicists, chemists, biologists, biomedical researchers, industry professionals, governmental scientists, and others whose work is impacted by nanotechnology. It will be an indispensable resource in academic, government, and industry libraries worldwide. The fields impacted by nanophysics extend from materials science and engineering to biotechnology, biomedical engineering, medicine, electrical engineering, pharmaceutical science, computer technology, aerospace engineering, mechanical engineering, food science, and beyond.

Download or read book Acta Physica Polonica written by and published by . This book was released on 1998 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Semiconducting Chalcogenide Glass I written by Robert Fairman and published by Academic Press. This book was released on 2004-05-10 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chalcogenide glass is made up of many elements from the Chalcogenide group. The glass is transparent to infrared light and is useful as a semiconductor in many electronic devices. For example, chalcogenide glass fibers are a component of devices used to perform laser surgery. This book is a comprehensive survey of the current state of science and technology in the field of chalcogenide semiconductor glasses. While the majority of the book deals with properties of chalcogenide glass, chapters also deal with industrial applications, synthesis and purification of chalcogenide glass, and glass structural modification. The first individual or collective monograph written by Eastern European scientists known to Western readers regarding structural and chemical changes in chalcogenide vitreous semiconductors(CVS)Chapters written by B.G. Kolomiets who discovered the properties of chalcogenide glass in 1955Provides evidence and discussion for problems discussed by authors from opposing positions.

Download or read book Comprehensive Nanoscience and Technology written by and published by Academic Press. This book was released on 2010-10-29 with total page 2785 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the Introduction: Nanotechnology and its underpinning sciences are progressing with unprecedented rapidity. With technical advances in a variety of nanoscale fabrication and manipulation technologies, the whole topical area is maturing into a vibrant field that is generating new scientific research and a burgeoning range of commercial applications, with an annual market already at the trillion dollar threshold. The means of fabricating and controlling matter on the nanoscale afford striking and unprecedented opportunities to exploit a variety of exotic phenomena such as quantum, nanophotonic and nanoelectromechanical effects. Moreover, researchers are elucidating new perspectives on the electronic and optical properties of matter because of the way that nanoscale materials bridge the disparate theories describing molecules and bulk matter. Surface phenomena also gain a greatly increased significance; even the well-known link between chemical reactivity and surface-to-volume ratio becomes a major determinant of physical properties, when it operates over nanoscale dimensions. Against this background, this comprehensive work is designed to address the need for a dynamic, authoritative and readily accessible source of information, capturing the full breadth of the subject. Its six volumes, covering a broad spectrum of disciplines including material sciences, chemistry, physics and life sciences, have been written and edited by an outstanding team of international experts. Addressing an extensive, cross-disciplinary audience, each chapter aims to cover key developments in a scholarly, readable and critical style, providing an indispensible first point of entry to the literature for scientists and technologists from interdisciplinary fields. The work focuses on the major classes of nanomaterials in terms of their synthesis, structure and applications, reviewing nanomaterials and their respective technologies in well-structured and comprehensive articles with extensive cross-references. It has been a constant surprise and delight to have found, amongst the rapidly escalating number who work in nanoscience and technology, so many highly esteemed authors willing to contribute. Sharing our anticipation of a major addition to the literature, they have also captured the excitement of the field itself in each carefully crafted chapter. Along with our painstaking and meticulous volume editors, full credit for the success of this enterprise must go to these individuals, together with our thanks for (largely) adhering to the given deadlines. Lastly, we record our sincere thanks and appreciation for the skills and professionalism of the numerous Elsevier staff who have been involved in this project, notably Fiona Geraghty, Megan Palmer and Greg Harris, and especially Donna De Weerd-Wilson who has steered it through from its inception. We have greatly enjoyed working with them all, as we have with each other.