Download or read book Study of Morin Transition in Hematite a Fe2O3 Nanoparticles by M ssbauer Spectroscopy written by Sajib Halder and published by . This book was released on 2020 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: The change in magnetic properties of hematite (a- Fe2O3) nanoparticles were investigated by observing the change of Morin transition fraction at different temperatures. X-ray diffraction, transimission electron microscope (TEM), vibrating sample magnetometer (VSM), and Mössbauer spectroscopy techniques applied to study the magnetic and structural properties of the sample. According to the XRD results the sample has a double phases with dominant hematite (a- Fe2O3) phase. The TEM analysis confirmed the prepared nanoparticles have a large size distribution with average diameter less than 20 nm. The Morin transition temperature of the sample was measured by both the magnetization measurements and Mössbauer study. The zero-field cooled (ZFC) and field-cooled (FC) magnetization measurements show the particles undergo a magnetic phase transition from a weakly ferromagnetic to antiferromagnetic phase at 250 K. Room temperature Mössbauer spectra show the superparamagnetic behavior of the materials where the magnetic moment fluctuates in all directions. Morin transition started just below (285 K) the room temperature. The Morin transition was found strongly temperature dependent and increased constantly with decreasing temperature. The magnetic and structural changes with changing the Morin transition fraction revealed important characterisitics about the sample. The Mössbauer spectra recorded at 140 K and below showed complete Morin transition, which indicates the materials are strongly antiferromagnetic. The average hyperfine magnetic field and isomer shift have similar relationship and both continuously increased with decreasing temperature. The weighted average Morin transition temperature for the sample obtained from Mössbauer studies is 265 15:8 K which is higher than the Morin transition found from the magnetization measurements (250 K) measured by VSM.
Download or read book Moessbauer Study of Synthetic Hematite Aggregates written by Mei-Zhen Dang and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthetic hematite aggregates that result from a process that may have industrial and environmental relevance are studied by Mossbauer spectroscopy at room temperature and liquid nitrogen temperature. The Mossbauer results are compared to measurements involving chemical analysis, scanning electron microscopy, and X-ray diffraction on the same samples. Factors such as the crystalline quality of the hematite and the overall sample purity (wt%Fe$\sb2$O$\sb3)$ are followed as functions of the known synthesis conditions. Pure bulk hematite (high quality $\alpha$-Fe$\sb2$O$\sb3$) serves as a reference throughout. Mossbauer spectroscopy is useful in two ways in this problem: (i) it can detect and identify iron-bearing impurities (i.e. non-hematite Fe-compounds), and (ii) it gives much detailed microscopic information on the intra-sample hematite. We find that all of the sulphur seen by chemical analysis probably resides in an iron-bearing compound which, most often, is probably a quenstetite-like material: Fe$\sb2$(SO$\sb4)\sb3\cdot$nH$\sb2$O (n = 9-11). The synthesis conditions are understood to determine both the hematite yield (or sample purity: wt%Fe$\sb2$O$\sb3$) and the intra-hematite crystalline quality, in that these two factors are correlated. Our interpretation of the room temperature Mossbauer spectra resolves coexisting bulk-like and high-defect-density regions whose relative amounts and sample-dependent Mossbauer characteristics can be quantified accurately. On going to liquid nitrogen temperature, a Morin transition is seen to have occurred in all regions of the most bulk-like samples, to have occurred in some regions of intermediate samples, or not to have occurred at all in the samples with the highest defect-density hematites. This illustrates the intricate interplay between microstructural details and cooperative magnetism in hematite materials.
Download or read book Iron Oxides in the Laboratory written by Udo Schwertmann and published by Wiley-VCH. This book was released on 1991-03-06 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents reliable, well-tested, up-to-date methods of synthesizing the major iron oxides. Such a collection is invaluable since iron oxides play an important role in numerous disciplines, including chemistry, soil science, medicine, corrosion science and aquatic and environmental chemistry. The emphasis is on techniques and apparatus that are readily accessible to the scientist. For students, the sections dealing with potential sources of error should prove extremely useful. Techniques for iron oxide characterization are also described in detail. Special Feature: color plates illustrating how the color of iron oxides varies with crystal structure, particle size, and metal substitution.
Download or read book M ssbauer Spectroscopy of Environmental Materials and Their Industrial Utilization written by Enver Murad and published by Springer Science & Business Media. This book was released on 2011-06-28 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mössbauer Spectroscopy of Environmental Materials and their Industrial Utilization provides a description of the properties of materials formed on the earth's surface, their synthetic analogs where applicable, and the products of their modifications in the course of natural processes, such as weathering, or in industrial processing as reflected in their Mössbauer spectra. Particular emphasis is placed on the way in which these processes can be observed and elucidated through the use of Mössbauer spectroscopy. The first chapter covers the basic theory of the Mössbauer effect and Chapters 2 and 3 deal with the nuts and bolts of experimental Mössbauer spectroscopy. The principles of these first three chapters, illustrated with many case studies, are applied to different areas of interest in Chapters 4 through 12. The book is directed to a broad audience ranging from graduate students in environmental sciences or chemical engineering with little or no expertise in Mössbauer spectroscopy to researchers from other disciplines who are familiar with this technique but wish to learn more about possible applications to environmental materials and issues.
Download or read book Classic and Advanced Ceramics written by Robert B. Heimann and published by John Wiley & Sons. This book was released on 2010-04-16 with total page 573 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the author's lectures to graduate students of geosciences, physics, chemistry and materials science, this didactic handbook covers basic aspects of ceramics such as composition and structure as well as such advanced topics as achieving specific functionalities by choosing the right materials. The focus lies on the thermal transformation processes of natural raw materials to arrive at traditional structural ceramics and on the general physical principles of advanced functional ceramics. The book thus provides practice-oriented information to readers in research, development and engineering on how to understand, make and improve ceramics and derived products, while also serving as a rapid reference for the practitioner. The choice of topics and style of presentation make it equally useful for chemists, materials scientists, engineers and mineralogists.
Download or read book Canted Antiferromagnetism Hematite written by Allan H Morrish and published by World Scientific. This book was released on 1995-01-16 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hematite (α-Fe2O3), the stable oxide of iron, is a major constituent of soils, rocks and the earth's crust. It has unique magnetic properties that make it the prototype for the class of materials known as canted antiferromagnets.This book has no equivalent. The mean-field theory is treated in detail, and thus the book is a useful text for students mastering this general method. Information obtained by a wide variety of experimental methods is provided. These techniques include x-ray and neutron diffraction; electron magnetic resonance; Mössbauer spectroscopy; and thermal, optical, electrical and elastic measurements.
Download or read book Structure and Concentration of Point Defects in Selected Spinels and Simple Oxides written by Andrzej Stoklosa and published by . This book was released on 2023-05-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: It presents diagrams and numerical data of important properties of spinels and oxides in one useful volume. Material scientists and engineers developing new metal or oxide-based systems can use this data to calculate other useful parameters and compare the properties of different materials to select the best candidates for intended use.
Download or read book Deep Earth written by Hidenori Terasaki and published by John Wiley & Sons. This book was released on 2016-03-07 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deep Earth: Physics and Chemistry of the Lower Mantle and Core highlights recent advances and the latest views of the deep Earth from theoretical, experimental, and observational approaches and offers insight into future research directions on the deep Earth. In recent years, we have just reached a stage where we can perform measurements at the conditions of the center part of the Earth using state-of-the-art techniques, and many reports on the physical and chemical properties of the deep Earth have come out very recently. Novel theoretical models have been complementary to this breakthrough. These new inputs enable us to compare directly with results of precise geophysical and geochemical observations. This volume highlights the recent significant advancements in our understanding of the deep Earth that have occurred as a result, including contributions from mineral/rock physics, geophysics, and geochemistry that relate to the topics of: I. Thermal structure of the lower mantle and core II. Structure, anisotropy, and plasticity of deep Earth materials III. Physical properties of the deep interior IV. Chemistry and phase relations in the lower mantle and core V. Volatiles in the deep Earth The volume will be a valuable resource for researchers and students who study the Earth's interior. The topics of this volume are multidisciplinary, and therefore will be useful to students from a wide variety of fields in the Earth Sciences.
Download or read book Comparative Crystal Chemistry written by Robert M. Hazen and published by Wiley. This book was released on 1982-11-09 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of the study of crystal structures as affected by temperature, pressure, and composition. Consolidates the diverse literature on the acquisition and analysis of high-temperature and high-pressure crystallographic data. Provides a step-by-step guide to operation of single-crystal x-ray devices. Summarizes the results of several dozen studies utilizing high-temperature and high-pressure crystallographic techniques and instruments.
Download or read book Sustainable Catalytic Processes written by Basudeb Saha and published by Newnes. This book was released on 2015-06-11 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of catalysts is the most sophisticated art in chemical sciences. It can be read like a story book when the critical scientific contents are presented in a chronological manner with short and simple sentences. This book will meets these criteria. To address the sustainability issues of existing chemical manufacturing processes or producing new chemicals, researchers are developing alternate catalysts to eliminate toxic chemicals use and by-products formation. Sustainable Catalytic Processes presents critical discussions of the progress of such catalytic development. This book of contemporary research results in sustainable catalysis area will benefit scientists in both industries and academia, and students to learn recent catalysts/process development. Reports the most recent developments in catalysis with a focus on environmentally friendly commercial processes, such as waste water treatment, alternate energy, etc Bridges the theory, necessary for the development of environmentally friendly processes, and their implementation through pilot plant and large scale Contains mainly laboratory scale data and encourages industrial scientists to test these processes on a pilot scale Includes work examples featuring the development of the new catalysts/processes using bio-renewable feedstock satisfactorily addressing environmental concerns Includes one chapter demonstrating real industrial examples motivating the industrial and academic researchers to pursue similar research
Download or read book Electronic Transitions and the High Pressure Chemistry and Physics of Solids written by H.G. Drickamer and published by Springer Science & Business Media. This book was released on 2013-03-13 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is no paucity of books on high pressure. Beginning with P. W. Bridgman's The Physics of High Pressure, books of general interest include the two-volume Physics and Chemistry of High Pressure, edited by R. S. Bradley, and the series, Advances in High Pressure Research, as well as the report on the Lake George Conference in 1960. Solid state physics is well represented by Solids Under Pressure, edited by Paul and Warschauer, by Physics of Solids at High Pressure, edited by Tomizuka and Emrick, and by Properties Physiques des Solides sous Pression, edited by Bloch, as well as by chapters in Volumes 6, 13, 17, and 19 of Solid State Physics, edited by Seitz, Turnbull, and Ehrenreich. Chemistry in gases and liquids is covered in Weale's Chemical Reactions at High Pressure, and Hamann's Physico-chemical Effects of Pressure. In addition to the coverage of techniques and calibrations in the above volumes, Modern Very High Pressure Techniques, edited by Wentorf, High Pressure Methods in Solid State Research, by C. C. Bradley, The Accurate Characterization of the High Pressure Environment, edited by E. C. Lloyd, and a chapter in Volume 11 of Solid State Physics are devoted entirely to this facet of high pressure research. It is not our plan either to supersede or extend these approaches. It is our purpose here to discuss the effect of high pressure on the electronic properties of solids.
Download or read book Synthesis Functionalization and Surface Treatment of Nanoparticles written by Marie-Isabelle Baraton and published by . This book was released on 2003 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesis, Functionalization and Surface Treatment of Nanoparticles is an area of crucial importance in the emerging field of nanotechnology. Controlling the surface chemical composition and mastering its modification at the nanometer scale are critical issues for high-added value applications involving nanoparticles. The basic applications of surface functionalization range from altering the wetting or adhesion characteristics and improving the nanoparticles dispersion in matrices to enhancing the catalytic properties and ordering the interfacial region, and such. The creation of specific surface sites on nanoparticles for selective molecular attachment is considered a promising approach for their applications in nanofabrication, nanopatterning, selfassembly, nanosensors, bioprobes, drug delivery, pigments, photocatalysis, LEDs, etc. This book presents novel and improved synthesis methods and approaches for controlling and functionalizing the nanoparticle surfaces to enhance the overall performance of the nanoparticles for targeted applications.
Download or read book Extractive Metallurgy 2 written by Alain Vignes and published by John Wiley & Sons. This book was released on 2013-03-01 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extractive metallurgy is the art and science of extracting metals from their ores and refining them. The production of metals and alloys from these source materials is still one of the most important and fundamental industries in both developed and developing economies around the world. The outputs and products are essential resources for the metallic, mechanical, electromagnetic, electrical and electronics industries (silicon is treated as a metal for these purposes). This series is devoted to the extraction of metals from ores, concentrates (enriched ores), scraps, and other sources and their refining to the state of either liquid metal before casting or to solid metals. The extraction and refining operations that are required may be carried out by various metallurgical reaction processes. Extractive Metallurgy 1 deals with the fundamentals of thermodynamics and kinetics of the reaction processes. Extractive Metallurgy 2 focuses on pyrometallurgical, hydrometallurgical, halide and electro-metallurgical (conversion) processes. Extractive Metallurgy 3 deals with the industrial processing operations, technologies, and process routes, in other words the sequence of steps or operations used to convert the ore to metal. Processes and operations are studied using the methodology of "chemical reaction engineering". As the fundamentals of the art and science of Extractive Metallurgy are infrequently taught as dedicated university or engineering schools courses, this series is intended both for students in the fields of Metallurgy and Mechanical Engineering who want to acquire this knowledge, and also for engineers put in charge of the operation of an industrial production unit or the development of a new process, who will need the basic knowledge of the corresponding technology.
Download or read book PbZn 2020 9th International Symposium on Lead and Zinc Processing written by A. Siegmund and published by Springer Nature. This book was released on 2020-01-24 with total page 937 pages. Available in PDF, EPUB and Kindle. Book excerpt: Established in 1970, the PbZn symposium series is considered the leading international technical forum for the lead and zinc processing industries. The PbZn 2020 volume addresses all aspects of current processing technologies for primary and secondary lead and zinc, as well as emerging technologies for both metals.
Download or read book M ssbauer Spectroscopy Applied to Inorganic Chemistry written by G.J Long and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1988 the Mossbauer effect community completed 30 years of continual contribution to the fields of nuclear physics, solid state science, and a variety of related disciplines. To celebrate this anniversary, Professor Gonser of the Universitat des Saarlandes has contributed a chapter to this volume on the history of the effect. Although Mossbauer spectroscopy has reached its mature years, the chapters in this volume illustrate that it is still a dynamic field of science with applications to topics ranging from permanent magnets to biologi cal mineralization. During the discussion of a possible chapter for this volume, a potential author asked, "Do we really need another Mossbauer book?" The editors responded in the affirmative because they believe that a volume of this type offers several advantages. First, it provides the author with an opportunity to write a personal view of the subject, either with or without extensive pedagogic content. Second, there is no artificially imposed restriction on length. In response to the question, "How long should my chapter be?," we have responded that it should be as long as is necessary to clearly present, explain, and evaluate the topic. In this type of book, it is not necessary to condense the topic into two, four, or eight pages as is now so often a requirement for publication in the research literature.
Download or read book Applied Sonochemistry written by T. J. Mason and published by Wiley-VCH. This book was released on 2002-05-06 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Power ultrasound has been used for many years in two specific industrial areas: cleaning and plastic welding. Over the last ten years an increasing interest has been shown in its potential for use over a much wider range of chemistry and processing which has been grouped together under the general title of sonochemistry. Most of these uses depend on the generation of acoustic cavitation in liquid media but this text, while underlining the importance of the physics and mathematics of cavitation, mainly concentrates on applications of the technology. After an introduction to the topic and some historical background to the uses of power ultrasound the general principles of acoustic cavitation are explored including some background physics, bubble dynamics and factors which influence cavitation. The remainder of the book incorporates a series of applications of sonochemistry which illustrate the types of physical and chemical effects of ultrasonically induced cavitation which will interest chemists and engineers alike. Amongst the major topics included are chemical synthesis, environmental protection and remediation of water, sewage and soils, polymer synthesis and processing, electrochemistry including both analytical and synthetic aspects and plating. The final chapter reviews the range of ultrasonic equipment available in the laboratory and the progress made towards the scale-up of sonochemistry. The level is introductory to semi-advanced and no topic has been taken to a particularly specialist level since it is intended that this should be of general interest to readers with a scientific background.
Download or read book ICAME 2005 written by P.-E. Lippens and published by Springer. This book was released on 2007-03-06 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an up-to-date overview of the Mössbauer effect in physics, chemistry, electrochemistry, catalysis, biology, medicine, geology, mineralogy, archaeology and materials science. Coverage details the most recent developments of the technique especially in the fields of nanoparticles, thin films, surfaces, interfaces, magnetism, experimentation, theory, medical and industrial applications and Mars exploration.
