Phase Diagram and Magnetic Excitations of BaFe2-xNixAs2: A Neutron Scattering Study


Book Description

This book studies the structural, magnetic and electronic properties of, as well as magnetic excitations in, high-temperature BaFe2-xNixAs2 superconductors using neutron diffraction and neutron spectroscopic methods. It describes the precise determination of the phase diagram of BaFe2-xNixAs2, which demonstrates strong magnetoelastic coupling and avoided quantum criticality driven by short-range incommensurate antiferromagnetic order, showing cluster spin glass behavior. It also identifies strong nematic spin correlations in the tetragonal state of uniaxial strained BaFe2-xNixAs2. The nematic correlations have similar temperature and doping dependence as resistivity anisotropy in detwinned samples, which suggests that they are intimately connected. Lastly, it investigates doping evolution of magnetic excitations in overdoped BaFe2-xNixAs2 and discusses the links with superconductivity. This book includes detailed neutron scattering results on BaFe2-xNixAs2 and an introduction to neutron scattering techniques, making it a useful guide for readers pursuing related research.




Iron-based Superconductors


Book Description

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




Iron-Based Superconductivity


Book Description

This volume presents an in-depth review of experimental and theoretical studies on the newly discovered Fe-based superconductors. Following the Introduction, which places iron-based superconductors in the context of other unconventional superconductors, the book is divided into three sections covering sample growth, experimental characterization, and theoretical understanding. To understand the complex structure-property relationships of these materials, results from a wide range of experimental techniques and theoretical approaches are described that probe the electronic and magnetic properties and offer insight into either itinerant or localized electronic states. The extensive reference lists provide a bridge to further reading. Iron-Based Superconductivity is essential reading for advanced undergraduate and graduate students as well as researchers active in the fields of condensed matter physics and materials science in general, particularly those with an interest in correlated metals, frustrated spin systems, superconductivity, and competing orders.










Iron-Based Superconducting Thin Films


Book Description

This book provides a modern introduction to the growth, characterization, and physics of iron-based superconducting thin films. Iron pnictide and iron chalcogenide compounds have become intensively studied key materials in condensed matter physics due to their potential for high temperature superconductivity. With maximum critical temperatures of around 60 K, the new superconductors rank first after the celebrated cuprates, and the latest announcements on ultrathin films promise even more. Thin film synthesis of these superconductors began in 2008 immediately after their discovery, and this growing research area has seen remarkable progress up to the present day, especially with regard to the iron chalcogenides FeSe and FeSe1-xTex, the iron pnictide BaFe2-xCoxAs2 and iron-oxyarsenides. This essential volume provides comprehensive, state-of-the-art coverage of iron-based superconducting thin films in topical chapters with detailed information on thin film synthesis and growth, analytical film characterization, interfaces, and various aspects on physics and materials properties. Current efforts towards technological applications and functional films are outlined and discussed. The development and latest results for monolayer FeSe films are also presented. This book serves as a key reference for students, lecturers, industry engineers, and academic researchers who would like to gain an overview of this complex and growing research area.




Neutron Scattering - Magnetic and Quantum Phenomena


Book Description

Neutron Scattering - Magnetic and Quantum Phenomena provides detailed coverage of the application of neutron scattering in condensed matter research. The book's primary aim is to enable researchers in a particular area to identify the aspects of their work where neutron scattering techniques might contribute, conceive the important experiments to be done, assess what is required to carry them out, write a successful proposal for one of the major user facilities, and perform the experiments under the guidance of the appropriate instrument scientist. An earlier series edited by Kurt Sköld and David L. Price, and published in the 1980s by Academic Press as three volumes in the series Methods of Experimental Physics, was very successful and remained the standard reference in the field for several years. This present work has similar goals, taking into account the advances in experimental techniques over the past quarter-century, for example, neutron reflectivity and spin-echo spectroscopy, and techniques for probing the dynamics of complex materials of technological relevance. This volume complements Price and Fernandez-Alonso (Eds.), Neutron Scattering - Fundamentals published in November 2013. - Covers the application of neutron scattering techniques in the study of quantum and magnetic phenomena, including superconductivity, multiferroics, and nanomagnetism - Presents up-to-date reviews of recent results, aimed at enabling the reader to identify new opportunities and plan neutron scattering experiments in their own field - Provides a good balance between theory and experimental techniques - Provides a complement to Price and Fernandez-Alonso (Eds.), Neutron Scattering - Fundamentals published in November 2013




Charge Dynamics in 122 Iron-Based Superconductors


Book Description

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.




Neutron Scattering with a Triple-Axis Spectrometer


Book Description

This practical guidebook is written for graduate and post-doctoral students, as well as for experienced researchers new to neutron scattering. Introductory chapters summarize useful scattering formulas and describe the components of a spectrometer. The authors then discuss the resolution function and focusing effects. Simple examples of phonon and magnon measurements are presented. Important chapters cover spurious effects in inelastic and elastic measurements, and how to avoid them. The last chapter covers techniques for, and applications of, polarization analysis.




Small-Angle Scattering


Book Description

SMALL-ANGLE SCATTERING A comprehensive and timely volume covering contemporary research, practical techniques, and theoretical approaches to SAXS and SANS Small-Angle Scattering: Theory, Instrumentation, Data, and Applications provides authoritative coverage of both small-angle X-ray scattering (SAXS), small-angle neutron scattering (SANS) and grazing incidence small-angle scattering (GISAS) including GISAXS and GISANS. This single-volume resource offers readers an up-to-date view of the state of the field, including the theoretical foundations, experimental methods, and practical applications of small-angle scattering (SAS) techniques including laboratory and synchrotron SAXS and reactor/spallation SANS. Organized into six chapters, the text first describes basic theory, instrumentation, and data analysis. The following chapters contain in-depth discussion on various applications of SAXS and SANS and GISAXS and GISANS, and on specific techniques for investigating structure and order in soft materials, biomolecules, and inorganic and magnetic materials. Author Ian Hamley draws from his more than thirty years’ experience working with many systems, instruments, and types of small-angle scattering experiments across most European facilities to present the most complete introduction to the field available. This book: Presents uniquely broad coverage of practical and theoretical approaches to SAXS and SANS Includes practical information on instrumentation and data analysis Offers useful examples and an accessible and concise presentation of topics Covers new developments in the techniques of SAXS and SANS, including GISAXS and GISANS Small-Angle Scattering: Theory, Instrumentation, Data, and Applications is a valuable source of detailed information for researchers and postgraduate students in the field, as well as other researchers using X-ray and neutron scattering to investigate soft materials, other nanostructured materials and biomolecules such as proteins.