Download or read book Studies on Diluted Oxide Magnetic Semiconductors for Spin Electronic Applications written by Germanas Peleckis and published by . This book was released on 2006 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Origin of Magnetism in Oxide Based Diluted Magnetic Semiconductors written by Numan Akdogan and published by LAP Lambert Academic Publishing. This book was released on 2014-07-23 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spintronics, short notation for spin-based electronics, is a research area which seeks to exploit the spin of electrons in addition to their charge in semiconductors. The basic idea is to combine the characteristics of existing magnetic devices with semiconductor devices in order to realize a new generation of devices that are much smaller, more energy efficient, non-volatile, and much faster than presently available. The key requirement in the development of such devices is an efficient injection, transfer and detection of spin-polarized current from a ferromagnetic material into a semiconductor. Due to the well known problem of a resistance mismatch at metal/semiconductor interfaces, hindering an effective spin injection, much interest is concentrated on the development of room-temperature ferromagnetic semiconductors. The aim of this book is to shed some light on the origin of room temperature ferromagnetism in oxide-based DMS materials whether it originates from clusters or from uniformly distributed magnetic atoms.
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 Zinc Oxide based Diluted Magnetic Semiconductors written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During my graduate research I have synthesized materials known as diluted magnetic semiconductors (DMS) as epitaxial thin film structures using the process of pulsed laser deposition (PLD). These materials are envisioned to be of importance in the emerging field of spintronics where the charge as well as the spin of the charge carriers can be combined to yield unique functionalities to yield novel devices including, on-chip memories, ultra-low power devices etc. The material of interest in this dissertation was zinc oxide, a wide bandgap optoelectronic semiconductor. ZnO has a bandgap of 3.3 eV. It is an ideal candidate for spintronics applications, because Zn is the last of the first row transition metals, which leads to pretty high solubility of transition metals such as Co, Mn and V in ZnO. In a diluted magnetic semiconductor a fraction of the host atoms is substituted by the transition metal dopant ion. We have found that we can synthesize very high quality, single phase and single crystalline Zn(TM)O thin films on basal plane sapphire single crystals (a-Al2O3). We have analyzed the magnetic properties of the three systems of ZnVO, ZnCoO and ZnMnO and found that ZnCoO and ZnMnO exhibit ferromagnetic ordering up to room temperature, when synthesized under high vacuum. In these conditions, the samples have a reasonable concentration of point defects which drive ZnO to n-type conductivity. By a combination of insitu and exsitu variation of parameters we have been able to tune the electronic and magnetic properties of these systems. From these studies we conclude that the main mechanism of magnetic ordering in these DMS materials is through a combination of defect related carrier induced exchange and bound magnetic polaron exchange. Device structures were fabricated using the as deposited samples to study the possibility of spin injection through semiconductors. We have observed that at low temperatures we see a considerable effect from this phenomenon in a m.
Download or read book Europium Monoxide written by Arnold S. Borukhovich and published by Springer. This book was released on 2018-03-22 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the physical characteristics and possible device applications of europium monoxide as well as materials based on it. It reveals the suitability of this material for device applications in super- and semiconductor spin electronics. Ferromagnetic semiconductors like europium monoxide have contributed to a fascinating research field in condensed matter physics. In the book are presented the electronic and magnetic properties and thermal and resonance parameters of this material, its peculiarities in external fields as a function of non-stoichiometry, doping level, both in single-crystal and thin-film states. Particular attention is paid to the possibility to use this monoxide or its solid solutions (composites) unconventionally for creating spin electronics structures which work at room temperature conditions. This book appeals to researchers, graduate students and professionals engaged in the development of semiconductor spin electronics and computer devices, technologists and theoretical physicists. It is important for the calculation, development and creation of spin memory devices for a quantum computer.
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 Study of Magneto transport Properties of Cobalt Doped Indium Oxide Dilute Magnetic Semiconductors written by Abhijit Ghosh and published by . This book was released on 2009 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxide based dilute magnetic semiconductors (DMS) are key materials for development of next generation multifunctional spintronics devices such as spin transistors and magnetic random access memories. However, the success of the spintronics devices critically depends on electrical and magneto-transport properties of DMS. This thesis investigates the effect of growth temperature and oxygen pressure on structural, optical, and magneto-transport properties of cobalt-doped indium oxide (In2O3:Co) DMS thin films. Thin films were grown under different partial oxygen pressures and substrate temperatures on quartz and sapphire substrates using pulsed laser deposition (PLD) technique. Structural, electrical, optical, and magneto-transport properties have been measured using various characterization techniques such as x-ray diffractometer (XRD), UV-visible spectroscopy, temperature dependent magneto-transport set-up, and superconducting quantum design magnetometer. The crystallinity of the films increases with increasing growth temperature as well as oxygen pressure during the growth as revealed by XRD. Hall effect and temperature dependence resistivity measurements reveal that the electrical transport properties (carrier density, mobility, and resistivity) in these films can be tuned by changing the growth temperature as well as oxygen pressure. Bandgap, measured using optical measurement, decreases with decrease in carrier concentration obtained from electrical measurement. Magneto-transport properties such as temperature dependent resistivity and magneto-resistance were found to be very sensitive to the micro-structural properties such as crystallinity as well as oxygen defect. These results provide basic information regarding electronic and magnetic properties of indium oxide as a prospective DMS for future spintronics applications.
Download or read book Defect Induced Magnetism in Oxide Semiconductors written by Parmod Kumar and published by Elsevier. This book was released on 2023-05-26 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defect-Induced Magnetism in Oxide Semiconductors provides an overview of the latest advances in defect engineering to create new magnetic materials and enable new technological applications. First, the book introduces the mechanisms, behavior, and theory of magnetism in oxide semiconductors and reviews the methods of inducing magnetism in these materials. Then, strategies such as pulsed laser deposition and RF sputtering to grow oxide nanostructured materials with induced magnetism are discussed. This is followed by a review of the most relevant postdeposition methods to induce magnetism in oxide semiconductors including annealing, ion irradiation, and ion implantation. Examples of defect-induced magnetism in oxide semiconductors are provided along with selected applications. This book is a suitable reference for academic researchers and practitioners and for people engaged in research and development in the disciplines of materials science and engineering. - Reviews the magnetic, electrical, dielectric and optical properties of oxide semiconductors with defect-induced magnetism - Discusses growth and post-deposition strategies to grow oxide nanostructured materials such as oxide thin films with defect-induced magnetism - Provides examples of materials with defect-induced magnetism such as zinc oxide, cerium dioxide, hafnium dioxide, and more
Download or read book Nanomagnetism and Spintronics written by Farzad Nasirpouri and published by World Scientific. This book was released on 2011 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomagnetism and spintronics are two close subfields of nanoscience, explaining the effect of substantial magnetic properties of matter when the materials fabrication is realized at a comparable length size. Nanomagnetism deals with the magnetic phenomena specific to the structures having dimensions in the submicron range. The fact that the electronic transport properties of materials are dependent on the magnetic properties' artificial nanostructures, i.e., giant magnetoresistance (GMR) or tunneling magnetoresistance (TMR), has revolutionized spintronics science and technology. This book explains the concepts of nanomagnetism and spintronics by viewing the most recent research works from internationally distinguished research groups. Placing special emphasis on crucial fundamental and technical aspects of nanomagnetism and spintronics, it serves as a one-stop reference for universities offering postgraduate programs in nanotechnology or related disciplines. This unique book deals with all three stages required for conducting research in nanomagnetism and spintronics including fabrication, characterization and applications of nanomagnetic and spintronics materials, providing general concepts and an insightful overview of this subject for research students and scientists from different backgrounds investigating the multidisciplinary area of nanotechnology.
Download or read book Magnetism and Spin Transport Studies on Indium Tin Oxide written by Ali Moraad Heydar Hakimi and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation reports on a detailed systematic study of the investigation into using Indium Oxide based materials in next generation spin-transport electronic applications. Initial studies focused on the optimisation of the electrical properties of Indium Oxide (In2O3) and Tin(Sn)-doped Indium Oxide (ITO) thin films grown using DC magnetron sputtering. The manipulation of various deposition parameters allowed the electrical properties to be tuned effectively. With the desire to create multi-functional spintronic devices, a dilute magnetic oxide system is developed where the In2O3 and ITO matrices are doped with low levels of transition metals, in particular, Co. Using a number of characterisation techniques, the origins of the magnetic response in these thin films is explored in great detail. In particular, powerful probes such as x-ray and optical magnetic circular dichroism are utilised. The major finding from these investigations is that the magnetism does not necessarily emanate from the Co dopants alone. In fact, Co dopants give a strictly paramagnetic response, suggesting that the magnetism observed may be a result of polarised electrons in localised donor states in the In2O3 and ITO hosts. Therefore, we believe that the origins of magnetism in these films is related to a hybridisation and charge transfer of electrons from a broad donor/defect-derived impurity band to a band of unoccupied 3d states at the Fermi level. The emergence of a very weak magnetic signal in pure ITO raises further questions as to the true origins of the ferromagnetic behaviour and supports a defect-related mechanism. To explore the suitability of ITO for a future in spintronics further, the performance of some metal ferromagnet/oxide multilayered structures was investigated. The investigations revealed a significant contribution to both the magnetic and magnetotransport properties from a superparamagnetic component giving some insight into the importance of the quality of interfaces between the metal ferromagnet/oxide layers and heterostructures. Using a three-dimensional focused-ion beam etching technique to fabricate submicronspin-valve devices with ITO spacer layers, current-perpendicular-to-plane magnetoresistance measurements were carried out to estimate the spin diffusion length of ITO at room temperature. In conjunction with a simplified Valet-Fert model, a spin asymmetry ratio for Co of 0.55 and spin diffusion length of 6±1 nm in semiconducting ITO at room temperature was estimated. These findings imply that spin information can be conserved and transported through In2O3 and ITO even up to and beyond room temperature.
Download or read book Dilute Magnetic Semiconductors Based on Gan and Zno written by Tom Kammermeier and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2010-05 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two wide band gap dilute magnetic semiconductors (DMS) Gd: GaN and Co: ZnO are among the most favored materials for spintronic applications. Despite intense research efforts during the last years, the origin of the magnetic order is still under debate. This work reports structural and magnetic investigations on these DMS materials employing several complementary techniques. The X-ray linear dichroism (XLD) has been used to gain element-specific insight into the local structure of dopants and cations. X-ray diffraction (XRD) has resulted in information about the global structural properties. Magnetic characterization by superconducting quantum interference device (SQUID) has been complemented by electron spin resonance (ESR) and X-ray magnetic circular dichroism (XMCD). This compilation of different techniques has yield new insight in the complex magnetic behavior of these wide band gap dilute magnetic semiconductor
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 Magnetism in Semiconducting Oxides written by Nguyen Hoa Hong and published by . This book was released on 2007-01-01 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: After the theoretical prediction of Dietl in 2000 in Science magazine for a possibility to make many semiconductors become high temperature ferromagnetic, there has been a strong wave of research arisen in numerous laboratories of physics and chemistry all over the world following this direction, with hope to find materials that are really useful for spintronics applications. If we can experimentally obtain such amazing compounds, certainly they must be very promising candidates for future technologies. Besides traditional types of semiconductors such as GaAs or GaN, etc, many oxides such as ZnO, TiO2, SnO2 or In2O3 have attracted a lot of attentions of researchers in the field of materials, due to their diversities in characteristics, so that they are interesting and challenging as well. Over the last few years, issues on magnetism of diluted magnetic semiconductors (lately also the research has been stretched further to diluted magnetic insulators as well), have become ones of the most interesting and questionable focuses in magnetism and science of the century. Since the subject is fashionable, in one side it is exciting for us, physicists and chemists, to deal with, but in the other side, it is hard because there are always a lot of competitions, and besides the compliments, a lot of criticisms that come along as well. Therefore, working on this field makes our everyday basis of research become very challenging, and inspirational, like we have a debate to surpass ourselves. In this book I would like to present to the readers a modest collection of review articles on magnetism of special types of semiconducting and insulating oxides written by outstanding scientists, who are ones of key players in the field of diluted magnetic semiconductors at the moment. The articles will cover from the theoretical models to the on-going experimental results. I hope that this book will bring you an overall view about the very up-to-date status of this new research field, as well as a fresh inspiration that we want to share with all our colleagues worldwide. One can see that many doors are still opened and plenty of things are waiting for us to explore altogether.
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 Novel Diluted Magnetic Semiconductor Materials based on Zinc Oxide written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary aim of this work was to develop a ZnO based diluted magnetic semiconductor (DMS) materials system which displays ferromagnetism above room temperature and to understand the origin of long-range ferromagnetic ordering in these systems. Recent developments in the field of spintronics (spin based electronics) have led to an extensive search for materials in which semiconducting properties can be integrated with magnetic properties to realize the objective of successful fabrication of spin-based devices. For these devices we require a high efficiency of spin current injection at room temperature. Diluted magnetic semiconductors (DMS) can serve this role, but they should not only display room temperature ferromagnetism (RTFM) but also be capable of generating spin polarized carriers. Transition metal doped ZnO has proved to be a potential candidate as a DMS showing RTFM. The origin of ferromagnetic ordering in ZnO is still under debate. However, the presence of magnetic secondary phases, composition fluctuations and nanoclusters could also explain the observation of ferromagnetism in the DMS samples. This encouraged us to investigate Cu-doped(+ ư spin in the 2+ valence state) ZnO system as a probable candidate exhibiting RTFM because neither metallic Cu nor its oxides (Cu2O or CuO) are ferromagnetic. The role of defects and free carriers on the ferromagnetic ordering of Cu-doped ZnO thin films was studied to ascertain the origin of ferromagnetism in this system. A novel non-equilibrium Pulsed Laser Deposition technique has been used to grow high quality epitaxial thin films of Cu:ZnO and (Co, Cu):ZnO on c-plane Sapphire by domain matching epitxay. Both the systems showed ferromagnetic ordering above 300K but Cu ions showed a much stronger ferromagnetic ordering than Co, especially at low concentrations (1-2 %) of Cu where we realized near 100% polarization. But, the incorporation of Cu resulted in a 2-order of magnitude rise in the resistivity from 10-1 t.
Download or read book Current Research on Functional Materials written by Yu Xun Wang and published by Trans Tech Publications Ltd. This book was released on 2014-10-20 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of functional materials is at the heart of technological needs and the forefront of materials research. This book provides a comprehensive and up-to-date collection of peer reviewed reports on functional materials. The 76 papers are grouped as follows: Chapter 1: Metallic, Magnetic, Electric and Photoelectric Functional Materials; Chapter 2: Nano and Inorganic Functional Materials; Chapter 3: Organic and Polymer Functional Materials; Chapter 4: Thin Film, Membrane and Coating Materials; Chapter 5: Biological and Environment Functional Materials.
Download or read book Spin Current written by Sadamichi Maekawa and published by Oxford University Press. This book was released on 2017 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a new branch of physics and technology, called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called "spin current", are manipulated and controlled together. This book is intended to provide an introduction and guide to the new physics and applications of spin current.
