Download or read book Spectroscopy of Superconducting Materials written by Eric Faulques and published by . This book was released on 1999 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume outlines the application of various spectroscopies to exotic superconductors. It covers analytic tools, Raman and ultrafast spectroscopy, and photoconductivity and includes theoretical overviews of lattice dynamics, electron-photon coupling, and plasma waves.

Download or read book High Temperature Superconducting Materials written by William E. Hatfield and published by CRC Press. This book was released on 1988-04-07 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emphasizing a multidisciplinary approach reflecting distinguished contributions by chemists, physicists, materials scientists, ceramicists, and electrical engineers, this timely reference gives a unified, comprehensive treatment of superconductivity encompassing background information for beginners and pioneering research for the most advanced specialists. Complete with over 500 citations of related literature and numerous diagrams, tables, and photographs, High-Temperature Superconducting Materials includes a review of oxide superconductors' structure/property relationships and factors affecting the conduction mechanism ... chronology of developments leading to the discovery of high-temperature superconducting materials ... basic physics of superconductivity ... discussions of XANES, ac Josephson effect, thermogravimetry, EPR, electron microscopy, infrared reflectance, Raman spectroscopy, magnetic susceptibilities, and specific heat studies ... unusual features of materials with high T[subscript c]'s ... processing techniques' effects on the properties of resultant materials ... and the effects of structure and chemical composition on the superconductivity transition temperature. An authoritative appraisal of a rapidly advancing field, High-Temperature Superconducting Materials is an indispensable reference for solid-state chemists and physicists, materials scientists and engineers, ceramicists, and electrical and electronics engineers as well as advanced undergraduate and graduate students interested in superconductivity. Book jacket.

Download or read book Fundamentals of Superconductivity written by Vladimir Z. Kresin and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent discovery of high-temperature superconductivity has resulted in a remarkable growth in the amount of research and the number of researchers working in this exciting field. Superconductivity is not a new phenomenon: in 1991 it will be 80 years old. Even though it was the newer discoveries which motivated us to write this book, the book itself is mainly a description of the fundamentals of the phenomenon. The book is written for a very broad audience, including students, engin eers, teachers, scientists, and others who are interested in learning about this exciting frontier of science. We have focused on the qualitative aspects, so that the reader can develop a basic understanding of the fundamental physics without getting bogged down in the details. Because of this approach, our list of refer ences is not comprehensive, and it is supplemented with a summary of additional reading consisting of monographs and selected review articles. (The articles we have referenced were either not reflected in the review articles on monographs or were milestones in the development of the field. ) In addition, some of the sections which can be skipped during the first reading have been marked with asterisks (*). Until recently, superconductivity was considered to belong to the field of low-temperature physics. This field was born, simultaneously with quantum physics, at the beginning of this century. Initially these two contemporaneous fields developed independently, but they soon became strongly coupled.

Download or read book Photoemission Spectroscopy on High Temperature Superconductor written by Wentao Zhang and published by Springer Science & Business Media. This book was released on 2012-08-22 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book mainly focuses on the study of the high-temperature superconductor Bi2Sr2CaCu2O8 by vacuum, ultra-violet, laser-based, angle-resolved photoemission spectroscopy (ARPES). A new form of electron coupling has been identified in Bi2212, which occurs in the superconducting state. For the first time, the Bogoliubov quasiparticle dispersion with a clear band back-bending has been observed with two peaks in the momentum distribution curve in the superconducting state at a low temperature. Readers will find useful information about the technique of angle-resolved photoemission and the study of high-temperature superconductors using this technique. Dr. Wentao Zhang received his PhD from the Institute of Physics at the Chinese Academy of Sciences.

Download or read book Spectroscopy of High Tc Superconductors written by N.M. Plakida and published by CRC Press. This book was released on 2003-03-20 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite ten years of intensive research, many questions remain unanswered concerning the nature of the electronic structure (Fermi vs non-Fermi liquid) and mechanisms of superconductivity. Spectroscopy of High-Tc Superconductors, A Theoretical View provides a current, comprehensive review of the experimental results and theoretical interpretations concerning elementary excitation spectra (electronic, phononic, charge, and spin fluctuations) in high-Tc superconductors (HTSC). It discusses accepted microscopic models that describe the electronic structure of the copper-oxide plane - the three-band model, the generalized Emery model, the one-band Hubbard model, different kinds of the t-J model, and the regular Kondo-lattice model - and compares them with ARPES experiments. Leading Russian researchers also consider experimental results obtained by Raman scattering both by phonons and electronic excitations, including magnetic excitations in antiferromagnets in the normal phase, on almost all the types of superconducting cuprates. The results are treated theoretically with the emphasis on features thought to be related to superconductivity. The book also gives an account of the properties of the microwave surface impedance and complex conductivity as functions of temperature common for high-quality single crystals: YBCO, BSCCO, TBCCO, and BKBO. The basics of the muon method and a review of experimental results for superconducting states of different HTSC-compounds are also presented. By offering a thorough examination of current research in the field, this book will appeal to advanced students and researchers working in superconductivity and theoretical condensed matter physics.

Download or read book Studies of High Temperature Superconductors written by A. V. Narlikar and published by Nova Publishers. This book was released on 1993 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Six papers by physicists from the Japan, India, Brazil and the US address some of the broad frontal issues of superconductivity, which include the mechanisms of high-temperature superconductivity, extra-high-temperature phenomena, the normal state pseudogap, the observations of the isotope effect in a host of different superconducting systems and their explanations, and the unusual features of strongly correlated electron systems like heavy fermions. Two extended papers explore the importance of positron annihilation and using electron spin resonance techniques to study superconducting materials. The treatments should be accessible to working scientists and engineers and to graduate students of physics, chemistry, materials science, solid-state electronics, and other disciplines.

Download or read book New Challenges in Superconductivity Experimental Advances and Emerging Theories written by J. Ashkenazi and published by Springer Science & Business Media. This book was released on 2005-11-02 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the 2004 University of Miami Workshop on Unconventional Superconductivity. The workshop was the fourth in a series of successful meetings on High-T Superconductivity and C related topics, which took place at the James L. Knight Physics Building on the University of Miami campus in Coral Gables, Florida, in January 1991, 1995, 1999, and 2004. The workshop consisted of two consecutive events: 1. NATO Advanced Research Workshop (ARW) on New Challenges in Superconductivity: Experimental Advances and Emerging Theories, held on January 11-14, 2004; 2. Symposium on Emerging Mechanisms for High Temperature Superconductivity (SEMHTS), held on January 15-16, 2004. It is hard to write a balanced preface to a volume like this one, yet at least we try to offer the reader a taste of what was happening in this workshop. There were close to a hundred scientists from around the world, albeit fewer Russians than we had originally hoped for. Nevertheless, the workshop was very lively and we trust that this is demonstrated in this volume. The workshop included high-quality presentations on state of the art works, yet a key issue, discussed by many, was how homogeneous the cuprates are. STM data, as well as other reports, showed that the cuprate superconductors (SC’s) studied were inhomogeneous, especially in the underdoped regime; while experiments, like ARPES and magnetoresistance have established the existence of a Fermi Surface (FS), at least above some doping level, in the cuprates.

Download or read book Charge Dynamics in 122 Iron Based Superconductors written by Aliaksei Charnukha and published by Springer Science & Business Media. This book was released on 2013-09-12 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis combines highly accurate optical spectroscopy data on the recently discovered iron-based high-temperature superconductors with an incisive theoretical analysis. Three outstanding results are reported: (1) The superconductivity-induced modification of the far-infrared conductivity of an iron arsenide with minimal chemical disorder is quantitatively described by means of a strong-coupling theory for spin fluctuation mediated Cooper pairing. The formalism developed in this thesis also describes prior spectroscopic data on more disordered compounds. (2) The same materials exhibit a sharp superconductivity-induced anomaly for photon energies around 2.5 eV, two orders of magnitude larger than the superconducting energy gap. The author provides a qualitative interpretation of this unprecedented observation, which is based on the multiband nature of the superconducting state. (3) The thesis also develops a comprehensive description of a superconducting, yet optically transparent iron chalcogenide compound. The author shows that this highly unusual behavior can be explained as a result of the nanoscopic coexistence of insulating and superconducting phases, and he uses a combination of two complementary experimental methods - scanning near-field optical microscopy and low-energy muon spin rotation - to directly image the phase coexistence and quantitatively determine the phase composition. These data have important implications for the interpretation of data from other experimental probes.

Download or read book Spectroscopy of Emerging Materials written by Eric C. Faulques and published by Springer Science & Business Media. This book was released on 2006-01-14 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive discussion of the key role of modern spectroscopic investigations in interdisciplinary materials science and engineering, covering emerging materials that are either absolutely novel or well-known materials with recently discovered, exciting properties. The types of spectroscopy discussed include optical, electronic and magnetic, UV-visible absorption, Rayleigh scattering, photoluminescence, vibrational, magnetic resonance, electron energy loss, EXAFS, XANES, optical tomography, time-resolved spectroscopy, and point contact spectroscopy. The materials studied are highly topical, with a focus on carbon and silicon nanomaterials including nanotubes, fullerenes, nanoclusters, metallic superconducting phases, molecular materials, magnetic and charge-stripe oxides, and biomaterials. Theoretical treatments are presented of molecular vibrational dynamics, vibration-induced decay of electronic excited states, nanoscale spin-orbit coupling in 2D Si-based structures, and the growth of semiconductor clusters.

Download or read book Angle Resolved Photoemission Spectroscopy on High Temperature Superconductors written by Junfeng He and published by Springer. This book was released on 2016-06-21 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book mainly focuses on the study of the high-temperature superconductor Bi2Sr2CaCu2O8+δ (Bi2212) and single-layer FeSe film grown on SrTiO3 (STO) substrate by means of angle-resolved photoemission spectroscopy (ARPES). It provides the first electronic evidence for the origin of the anomalous high-temperature superconductivity in single-layer FeSe grown on SrTiO3 substrate. Two coexisted sharp-mode couplings have been identified in superconducting Bi2212. The first ARPES study on single-layer FeSe/STO films has provided key insights into the electronic origin of superconductivity in this system. A phase diagram and electronic indication of high Tc and insulator to superconductor crossover have been established in the single-layer FeSe/STO films. Readers will find essential information on the techniques used and interesting physical phenomena observed by ARPES.

Download or read book High Temperature Superconductivity written by J. Ashkenazi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the University of Miami Workshop on the subject of "Electronic Structure and Mechanisms for High Temperature Super conductivity". The workshop was held at the James L. Knight Physics Building on the campus of the University of Miami, Coral Gables, 3-9 January 1991. Some 106 scientists from 12 countries attended this workshop, most of whom presented either invited or contributed papers. The reader will find in this volume a series of papers discussing the most im portant experimental and theoretical developments as of winter/spring 1990/1991. Despite more than four years of intensive research on high-T materials, there has c been considerable controversy both with respect to the interpretation of experiment and even more so in connection with the construction of an appropriate theory. In this regard, workshops such as this, gathering scientists with many viewpoints, and varying specialization, and fostering constructive discussions, are important in the de velopment of a common ground. Of major concern in the present context were the basic physical processes involved in high-temperature superconductivity.

Download or read book Tunneling Spectroscopy Studies of Superconductors written by Basu Dev Oli and published by . This book was released on 2021 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: In multiband superconductors, different bands at the Fermi surface contribute to the superconductivity with different magnitudes of superconducting gaps on different portions of the Fermi surface. Each band in a multiband superconductor has a condensate with an amplitude and phase that weakly interacts with the other bands' condensate. The coupling strength between the bands determines whether one or two superconducting transition temperatures are observed, and it is the key to many peculiar properties. In general, if there are two gaps of different magnitude, there are two different length scales associated with the suppression of these gaps in applied magnetic fields, for example. Therefore, effects of multigap superconductivity can be observed in superconducting vortices, which are twirls of supercurrents that are generated when a superconductor is placed in a magnetic field. Furthermore, the two superconducting order parameters in different bands are characterized by a magnitude and phase. In multiband superconductors, there are collective excitations corresponding to fluctuations of the relative phase of two order parameters, so-called the Leggett mode. The first material identified as multiband superconductor is Magnesium Diboride (MgB2) in 2001 with a critical temperature Tc of 39 K. MgB2 is a superconducting material with the highest transition temperature among all conventional BCS superconductors. It has two superconducting gaps \Delta_\pi ~ 2 meV and \Delta_\sigma\ ~ 7 meV and they arise from the existence of two bands \pi and \sigma bands of boron electrons. The discovery of superconductivity in MgB2 renewed interest in the field of multiband superconductivity. MgB2 has attracted many scientists' attention both for the fundamental importance of understanding the multiband superconductivity and possible applications such as magnets, power cables, bolometers, Josephson junction-based electronic devices, and radio-frequency cavities. Afterward, other materials have been identified as multiband superconductors such as NbSe2, the family of iron-based superconductors, heavy fermion superconductors, multilayer cuprates, borocarbides, etc. This dissertation uses tunneling experiments to highlight multiband superconductivity features in two systems, namely MgB2 thin films and ultrathin films of Pb. Further, we use multiple techniques to study a superconducting material, nitrogen-doped niobium, used for superconducting radio-frequency cavities. For the project on MgB2, MgB2/Native-Oxide/Ag planar junctions are fabricated and characterized down to 2.1 K and in the magnetic field parallel to the sample surface up to 6 Tesla. This work investigates how pairbreaking affects the magnitude and phase of the order parameter in a multiband superconductor. The tunneling spectra are analyzed in the framework of a two-band model developed by our theory collaborator Prof. Alex Gurevich, Old Dominion University. The model allows the extraction of the pair-breaking parameters among other quantities. The analysis shows that the order parameter in the ? band is quickly suppressed in the field, the ? band is cleaner than the ? band. The ratio of pairbreaking parameter in the ? band to the ? band rapidly increases at fields higher than ~0.1 T and then plateau at higher fields. This transition around 0.1 T magnetic field suggests a phase decoupling in the two bands of MgB2. Below the transition, the two bands are phase-locked, so mostly, the superconductivity in the ? band is affected, and after phase decoupling, both bands are affected by the applied field. These results are important for a basic understanding of multiband superconductors and the application implications of this material. This phase decoupling has a new and profound consequence on the superconducting state of a multiband superconductor that has been theoretically predicted and never observed experimentally. For the Pb project, ultrathin films of Pb in ultrahigh vacuum conditions are deposited by e-beam evaporation and characterized with low-temperature scanning tunneling microscopy and spectroscopy (STM/STS). The STM/STS allows measuring the electronic density of states with the highest spatial resolution down to atomic scale. The shape of a superconducting vortex core is determined by the superconducting gap and the Fermi velocity, and the STM allows to map anisotropies of these quantities spatially. The vortex cores of Pb film show a complex shape that evolves from triangular at short distances from the center to a six-fold symmetric star shape farther away from the center. These details are very subtle, and they can be highlighted only if one works within the clean limit (to avoid the averaging effect of the scattering) and by fabricating the heterostructure that pins the vortices spatially. The complex vortex core shape reflects the anisotropy of the two bands that contribute to superconductivity in this material. For the project on Niobium, cold and hot spots from nitrogen-doped Nb cutouts are characterized by low temperature scanning tunneling microscopy and spectroscopy (STM/STS) combined with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The radiofrequency (RF) measurements of the quality factor and temperature mapping on an N-doped Nb superconducting resonator cavity are carried out at Jefferson Laboratory before cutting out the samples. This work aims to identify possible sources of excess dissipation in hot spots and relate them to the surface chemical composition and superconducting properties. The temperature mapping revealed a strong effect of the cavity cooldown rate on the intensities of hot spots and their spatial distribution, which indicates a significant contribution of trapped vortices to the RF dissipation. SEM images acquired on the cold and hot spots using a secondary electron detector show absence of residual hydride scars and niobium nitrides on their surface. Angle-resolved XPS measurements on the native surface of these samples revealed higher oxidized Nb 3d states on the N-doped Nb cold spots, which is supported by XPS depth profiles done on the samples by Argon ion sputtering. Argon ion sputtering of oxidized Nb removes oxygen preferentially from Nb2O5 and diffuses to bulk, thickening the lower oxidation state layers. The proximity theory framework's tunneling spectra analysis suggests hot spots have stronger pairbreaking due to a weakly reduced pair potential, a thicker metallic suboxide layer, and a wide distribution of the contact resistance. STM imaging of vortex cores shows a triangular vortex lattice in both samples, and the coherence length is nearly the same in hot and cold spots. The experimental data analysis suggests weakly degraded superconducting properties at the surface of hot spot regions are not the primary sources of RF losses. Instead, they are the regions where vortices nucleate first and get trapped during cooling down. These experimental techniques and findings will be crucial in helping to qualify new recipes for SRF cavity production and to boost their performance.

Download or read book Engineering Properties of Superconducting Materials written by Tim Coombs and published by MDPI. This book was released on 2021-06-09 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plastic (and microplastic) pollution has been described as one of the greatest environmental challenges of our time, and a hallmark of the human-driven epoch known as the Anthropocene. It has gained the attention of the general public, governments, and environmental scientists worldwide. To date, the main focus has been on plastics in the marine environment, but interest in the presence and effects of plastics in freshwaters has increased in the recent years. The occurrence of plastics within inland lakes and rivers, as well as their biota, has been demonstrated. Experiments with freshwater organisms have started to explore the direct and indirect effects resulting from plastic exposure. There is a clear need for further research, and a dedicated space for its dissemination. This book is devoted to highlighting current research from around the world on the prevalence, fate, and effects of plastic in freshwater environments.

Download or read book Iron based Superconductors written by Nan Lin Wang and published by CRC Press. This book was released on 2012-11-19 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: From fundamental physics point of view, iron-based superconductors have properties that are more amenable to band structural calculations. This book reviews the progress made in this fascinating field. With contributions from leading experts, the book provides a guide to understanding materials, physical properties, and superconductivity mechanism aspects, and is important for students and beginners to have an overall view of the recent progress in this active field.

Download or read book Superconductivity written by Vladimir Rem Romanovskii and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents current research from across the globe in the study of superconductivity theory, materials and applications. Topics discussed include tunnelling spectroscopy of novel layered superconductors; stability conditions of high-Tc superconductors; a study of the superconducting phase in metallic superconductors; numerical calculation of trapped magnetic field for bulk superconductors; ion modified high-Tc Josephson junctions and SQUIDS; and vortices in high temperature superconductors.

Download or read book New Challenges in Superconductivity Experimental Advances and Emerging Theories written by J. Ashkenazi and published by Springer Science & Business. This book was released on 2005-11-02 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the 2004 University of Miami Workshop on Unconventional Superconductivity. The workshop was the fourth in a series of successful meetings on High-T Superconductivity and C related topics, which took place at the James L. Knight Physics Building on the University of Miami campus in Coral Gables, Florida, in January 1991, 1995, 1999, and 2004. The workshop consisted of two consecutive events: 1. NATO Advanced Research Workshop (ARW) on New Challenges in Superconductivity: Experimental Advances and Emerging Theories, held on January 11-14, 2004; 2. Symposium on Emerging Mechanisms for High Temperature Superconductivity (SEMHTS), held on January 15-16, 2004. It is hard to write a balanced preface to a volume like this one, yet at least we try to offer the reader a taste of what was happening in this workshop. There were close to a hundred scientists from around the world, albeit fewer Russians than we had originally hoped for. Nevertheless, the workshop was very lively and we trust that this is demonstrated in this volume. The workshop included high-quality presentations on state of the art works, yet a key issue, discussed by many, was how homogeneous the cuprates are. STM data, as well as other reports, showed that the cuprate superconductors (SC’s) studied were inhomogeneous, especially in the underdoped regime; while experiments, like ARPES and magnetoresistance have established the existence of a Fermi Surface (FS), at least above some doping level, in the cuprates.

Download or read book Dynamics of Magnetic Fluctuations in High Temperature Superconductors written by George Reiter and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: This NATO Advanced Research Workshop was held at a time when there was little consensus as to the mechanism for high temperature superconductivity, in the context of a world undergoing major changes in its political alignments and sense of the possibility for the future. It was characterized by generosity in the sharing of our uncertainties and speculations, as was appropriate for both the subject matter and the context. The workshop was organized, of necessity around the experimental work, as is this volume. Where the theoretical work is directly relevant to particular experiments, it is included in the appropriate sections with them. Most of the participants felt strongly that magnetic fluctuations played an important role in the mechanism for high T c, although with the exception of the IlS R work reported by Luke showing results inconsistent with the anyon picture, and the work on flux phases by Lederer, the mechanism remained an issue in the background. A major focus was the phenomenological interpretation of the NMR data.