Pressure-Induced Phase Transitions in AB2X4 Chalcogenide Compounds
Pressure-Induced Phase Transitions in AB2X4 Chalcogenide Compounds

Author: Francisco Javier Manjon

Publisher: Springer

Published: 2016-08-23

Total Pages: 0

ISBN-13: 9783662521892

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This book on pressure-induced phase transitions in AB2X4 chalcogenide compounds deals with one important AmBnXp material. The interest in these materials is caused by their properties. The results are discussed for three main groups of structural families: cubic-spinel structures, defective tetragonal structures, and other structures like layered and wurtzite-type modifications. A systematic analysis of the behavior of cubic (spinel), tetragonal (defect chalcopyrites and stannites) and other crystal modifications of AB2X4 compounds under hydrostatic pressure is performed. The behavior of AIIAl2S4, AIIGa2S4, AIIAl2Se4 and AIIGa2Se4 compounds with defective tetragonal structures, compounds with layered and wurtzite structures under hydrostatic pressure and the pressure dependence of the band gap, lattice parameters, interatomic distances, vibrational modes and pressure-induced phase transitions is discussed. Many of these compounds, except oxide spinels, undergo a pressure-induced phase transition towards the rocksalt-type structure. The phase transition is preceded by disorder in the cation sublattice. The dependence of the transition pressure to the rocksalt-type structure as a function of the compound ionicity and the size criterion is analyzed. At high pressures, all ordered-vacancy compounds are found to exhibit a band anticrossing between several conduction bands that leads to a strong decrease of its pressure coefficient and consequently to a strong non-linear pressure dependence of the direct bandgap energy. Theoretical studies of phase transitions in several ordered-vacancy compounds reveal that the existence of ordered vacancies alter the cation-anion bond distances and their compressibilities. The book is written for students, Ph D. students and specialists in materials science, phase transitions and new materials.

Pressure-Induced Phase Transitions in AB2X4 Chalcogenide Compounds
Pressure-Induced Phase Transitions in AB2X4 Chalcogenide Compounds

Author: Francisco Javier Manjon

Publisher: Springer Science & Business Media

Published: 2014-01-21

Total Pages: 248

ISBN-13: 3642403670

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This book on pressure-induced phase transitions in AB2X4 chalcogenide compounds deals with one important AmBnXp material. The interest in these materials is caused by their properties. The results are discussed for three main groups of structural families: cubic-spinel structures, defective tetragonal structures, and other structures like layered and wurtzite-type modifications. A systematic analysis of the behavior of cubic (spinel), tetragonal (defect chalcopyrites and stannites) and other crystal modifications of AB2X4 compounds under hydrostatic pressure is performed. The behavior of AIIAl2S4, AIIGa2S4, AIIAl2Se4 and AIIGa2Se4 compounds with defective tetragonal structures, compounds with layered and wurtzite structures under hydrostatic pressure and the pressure dependence of the band gap, lattice parameters, interatomic distances, vibrational modes and pressure-induced phase transitions is discussed. Many of these compounds, except oxide spinels, undergo a pressure-induced phase transition towards the rocksalt-type structure. The phase transition is preceded by disorder in the cation sublattice. The dependence of the transition pressure to the rocksalt-type structure as a function of the compound ionicity and the size criterion is analyzed. At high pressures, all ordered-vacancy compounds are found to exhibit a band anticrossing between several conduction bands that leads to a strong decrease of its pressure coefficient and consequently to a strong non-linear pressure dependence of the direct bandgap energy. Theoretical studies of phase transitions in several ordered-vacancy compounds reveal that the existence of ordered vacancies alter the cation-anion bond distances and their compressibilities. The book is written for students, Ph D. students and specialists in materials science, phase transitions and new materials.

Nanohybrids in Environmental & Biomedical Applications
Nanohybrids in Environmental & Biomedical Applications

Author: Surender Kumar Sharma

Publisher: CRC Press

Published: 2019-07-09

Total Pages: 396

ISBN-13: 1351256831

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Heterostructured nanoparticles have the capability for a broad range of novel and enhanced properties, which leads to appealing biomedical and environmental applications. This timely new book addresses the design and preparation of multiphase nanomaterials with desired size, shape, phase composition, and crystallinity, as well as their current applications. It emphasizes key examples to motivate deeper studies, including nanomaterial-based hyperthermia treatment of cancer, nanohybrids for water purification, nanostructures used in the removal or detection of bioagents from waste water, and so on. Features Presents state of the art research on heterostructured nanomaterials, from their synthesis and physiochemical properties to current environmental and biological applications. Includes details on toxicity and risk assessment of multifunctional nanomaterials. Discusses recent developments and utilization in healthcare by leading experts. Introduces the main features of functionalization of nanomaterials in terms of desired size, shape, phase composition, surface functionalization/coating, toxicity, and geometry. Emphasizes practical applications in the environmental and biomedical sectors.

Pressure-Induced Phase Transformations (Volume II)
Pressure-Induced Phase Transformations (Volume II)

Author: Daniel Errandonea

Publisher: Mdpi AG

Published: 2023-08-25

Total Pages: 0

ISBN-13: 9783036585642

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The study of phase transitions in materials under high pressure and high temperature is a very active research field. In the last few decades, many important discoveries have been made thanks to the development of experimental techniques and computer simulation methods. Many of these achievements affect various research fields ranging from solid-state physics, chemistry, and materials science to geophysics. They not only involve deepening knowledge on solid-solid phase transitions, but also a better understanding of melting under compression. These modern discoveries, as well as the impact of pressure on structural, chemical, and physical properties, are central to the current Special Issue. Amongst other topics, it places particular emphasis on phase transitions and their effects on different physical properties.

Pressure-Induced Phase Transformations
Pressure-Induced Phase Transformations

Author: Daniel Errandonea

Publisher:

Published: 2020-09-04

Total Pages: 224

ISBN-13: 9783039368167

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This book is a printed edition of the Special Issue of Crystals entitled Pressure-Induced Phase Transformations. It includes selected articles on the behavior of matter under high-pressure and high-temperature conditions, describing and discussing contemporary achievements, which were selected based on their relevance and scientific quality.

Pressure-induced Phase Transitions in Select Molybdates and Tungstates
Pressure-induced Phase Transitions in Select Molybdates and Tungstates

Author: Paul Robert Scott

Publisher:

Published: 2013

Total Pages: 150

ISBN-13:

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Mao-Bell and symmetric diamond anvil cells were used to study the effect of high-pressure on a series of tungstate and molybdate compounds. The experimental techniques of powder x-ray diffraction and Raman spectroscopy were employed to gain an understanding of the observed phase transitions. Bi2MoO6, exhibited a phase transition at ~6.8 GPa that was observed by a stiffening of its bulk modulus from 51 GPa, for the low-pressure phase, to 141.5 GPa for the high-pressure phase. Bi2W2O9 exhibited a phase transition at ~11 GPa that was observed by a change in the x-ray diffraction pattern. Bi2WO6 exhibited a phase transition between ~4.8 GPa and 8.3 GPa that was observed by a stiffening of its bulk modulus from 52.2 GPa, for the low-pressure phase, to 121.8 GPa for the high-pressure phase. La2Mo4O15 exhibited two phase transitions one at 2 GPa and another at 17 GPa. The transition at 2 GPa was observed as a change in the x-ray diffraction pattern and has yet to be identified. The transition at 17 GPa was to a glassy, pressure-induced amorphization, state. Sm2Mo4O15 exhibited a phase transition at 5.4 GPa. This transition was observed as a change in the x-ray diffraction pattern and has yet to be identified. MgNb2O6 exhibited a phase transition at 10.3 GPa. This transition was observed in both x-ray diffraction and Raman spectroscopy. KNbW2O9 exhibited no signs of a phase change up to a pressure of 35 GPa.

Electrochemistry of Metal Chalcogenides
Electrochemistry of Metal Chalcogenides

Author: Mirtat Bouroushian

Publisher: Springer Science & Business Media

Published: 2010-04-23

Total Pages: 365

ISBN-13: 3642039677

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The author provides a unified account of the electrochemical material science of metal chalcogenide (MCh) compounds and alloys with regard to their synthesis, processing and applications. Starting with the chemical fundamentals of the chalcogens and their major compounds, the initial part of the book includes a systematic description of the MCh solids on the basis of the Periodic Table in terms of their structures and key properties. This is followed by a general discussion on the electrochemistry of chalcogen species, and the principles underlying the electrochemical formation of inorganic compounds/alloys. The core of the book offers an insight into available experimental results and inferences regarding the electrochemical preparation and microstructural control of conventional and novel MCh structures. It also aims to survey their photoelectrochemistry, both from a material-oriented point of view and as connected to specific processes such as photocatalysis and solar energy conversion. Finally, the book illustrates the relevance of MCh materials to various applications of electrochemical interest such as (electro)catalysis in fuel cells, energy storage with intercalation electrodes, and ion sensing.

Introduction to Frustrated Magnetism
Introduction to Frustrated Magnetism

Author: Claudine Lacroix

Publisher: Springer Science & Business Media

Published: 2011-01-12

Total Pages: 682

ISBN-13: 3642105890

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The field of highly frustrated magnetism has developed considerably and expanded over the last 15 years. Issuing from canonical geometric frustration of interactions, it now extends over other aspects with many degrees of freedom such as magneto-elastic couplings, orbital degrees of freedom, dilution effects, and electron doping. Its is thus shown here that the concept of frustration impacts on many other fields in physics than magnetism. This book represents a state-of-the-art review aimed at a broad audience with tutorial chapters and more topical ones, encompassing solid-state chemistry, experimental and theoretical physics.