Download or read book Probing Magnetic Fluctuations Close to Quantum Critical Points by Neutron Scattering written by Anna Zita Hüsges and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Fluctuations and Clusters in the Itinerant Ferromagnet Ni V Close to a Disordered Quantum Critical Point written by Ruizhe Wang and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of quantum phase transitions (QPT) is a promising route to comprehend the origin of unconventional properties in strongly correlated electron systems. Recent theories predict a new quantum critical point (QCP) in disordered itinerant system with exotic properties such as observable quantum Griffiths phase (QGP). The binary alloy Ni-V presents such QGP and looks like the best example to study a ferromagnetic QPT with controlled disorder. In this work, we investigate further Ni-V with advanced local methods using neutron scattering and [mu]SR techniques. Initial doubts on sample quality and sample-dependent impact on different magnetic phases and disordered scenarios can be resolved. A structural characterization indicates that the investigated Ni-V samples show a high-quality chemical structure with expected random atomic distribution. We provide direct evidence of the "disorder" with [mu]SR methods. We clarify essential details of the Ni-V phase diagram such as the nature and the boundaries of ferromagnetic and cluster glass phases. These new data reinforce the location of the QCP and the limits of the QGP in Ni-V. The main results are consistent with theories predicting an infinite randomness quantum critical point associated with a QGP.

Download or read book Neutron Scattering Study Of Ni V And Ce Ni Cu Sn Close To The Onset Of Magnetic Order written by Shiva Bhattarai and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strongly correlated electron systems are at the borderline of competing phases and can be tuned through different ground states by slight modifications. Therefore, they are good examples to study a quantum phase transition (QPT), to reveal how a quantum critical point (QCP) at zero temperature is responsible for the unconventional properties observed at finite temperatures. QPTs are zero-temperature phase transitions, they are more complex and less understood than common phase transitions at finite temperatures. Examples are lacking, especially in the case where disorder is involved. Recent theories predict the possibility of an exotic quantum critical point in itinerant magnets with induced disorder that is accompanied by a quantum Griffiths phase. To explore such unconventional properties in close neighborhood to a magnetic phase, we aim to reveal the relevant quantum critical fluctuations with neutron scattering. We select systems with different magnetic order and choose as tuning parameter chemical substitution to study the effect of disorder. Such experimental study aims to find key elements of a QCP with disorder. The two systems are the ferromagnetic (FM) alloy, Ni-V, tuned by the V-concentration into a paramagnetic phase, and the non-magnetic Kondo semimetal, Ce(Cu,Ni)Sn, tuned by Cu concentration into an antiferromagnetic state. We apply different neutron scattering techniques and simple models to get essential characteristics of the magnetic correlations and fluctuations close to the QCP. Ni-V is a simple FM-alloy with a random atomic distribution that undergoes a quantum phase transition from a ferromagnetic to a paramagnetic state with sufficient substitution of Ni by V. First indication of a quantum Griffiths phase came from magnetization and [mu]SR data, but the scale of the magnetic clusters remained elusive. Optimized small angle neutron scattering (SANS) data on different polycrystalline Ni-V samples close to the QCP finally show a small magnetic scattering response within the FM state. Using full polarization analysis, we discover short-range correlations of order of several nanometers. In addition, the polarized SANS data show evidence of long-range order. The coexistence of magnetic clusters and long-range ordered domains explain the unusual properties of this disordered FM with a QCP. These results agree with the expectations of a disordered QCP with a quantum Griffith phase. The non-magnetic anisotropic Kondo insulator, CeNiSn, presents a rather unique magnetic excitation spectrum with gaps. Cu doping leads to an antiferromagnetic ordered state with a small magnetic moment. We collected the first inelastic neutron scattering data of a single crystalline sample with Cu concentration at the onset of the magnetic order and revealed the magnetic excitation spectrum at a specific wave vector. It does not show a gap anymore, but magnetic order. In addition, we identify a fluctuation spectrum, including one-dimensional critical magnetic fluctuations. These first data already shed some light on the complex behavior of this Kondo semimetal driven by anisotropic hybridization and disorder. Overall these neutron scattering data reveal relevant quantum fluctuations close to onset of magnetic order that help to characterize the nature of the transition

Download or read book Thermal neutron Scattering and Critical Magnetic Fluctuations written by O. W. Dietrich and published by . This book was released on 1970 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phase Diagram and Magnetic Excitations of BaFe2 xNixAs2 A Neutron Scattering Study written by Xingye Lu and published by Springer. This book was released on 2017-07-10 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Statistical Mechanics Entropy Order Parameters and Complexity written by James P. Sethna and published by Oxford University Press. This book was released on 2021-01-26 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Statistical mechanics is our tool for deriving the laws that emerge from complex systems. Sethna's text distills the subject to be accessible to those in all realms of science and engineering — avoiding extensive use of quantum mechanics, thermodynamics, and molecular physics. Statistical mechanics explains how bacteria search for food, and how DNA replication is proof-read in biology; optimizes data compression, and explains transitions in complexity in computer science; explains the onset of chaos, and launched random matrix theory in mathematics; addresses extreme events in engineering; and models pandemics and language usage in the social sciences. Sethna's exercises introduce physicists to these triumphs and a hundred others — broadening the horizons of scholars both practicing and nascent. Flipped classrooms and remote learning can now rely on 33 pre-class exercises that test reading comprehension (Emergent vs. fundamental; Weirdness in high dimensions; Aging, entropy and DNA), and 70 in-class activities that illuminate and broaden knowledge (Card shuffling; Human correlations; Crackling noises). Science is awash in information, providing ready access to definitions, explanations, and pedagogy. Sethna's text focuses on the tools we use to create new laws, and on the fascinating simple behavior in complex systems that statistical mechanics explains.

Download or read book Critical Magnetic Fluctuations in Localized and Itinerant Magnets Studied by Neutron Scattering written by Daniel Lamago Kaffo and published by . This book was released on 2006 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Neutron Scattering Proceedings Of The Third Summer School On Neutron Scattering written by Albert Furrer and published by World Scientific. This book was released on 1995-10-12 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proceedings provide a topical survey of the static and dynamical magnetic properties of condensed matter studied by neutron scattering which has been the key technique in this field for a long time. The static aspects deal with the determination of long-range ordered spin structures and magnetization densities. The dynamic aspects concentrate on the determination of magnetic excitations such as spin waves and crystal-field transitions. The use of polarized-neutron techniques is particularly emphasized. All these topics are thoroughly introduced, methodically discussed, and highlighted with recent experimental results obtained for a vast variety of magnetic materials (e.g., strongly correlated electron systems, multilayers, nanocrystals, molecular complexes, etc.) by acknowledged experts. Other experimental methods (x-ray scattering, muon spin rotation) in the study of magnetism are compared to neutron scattering.

Download or read book Neutron Scattering Magnetic and Quantum Phenomena written by and published by Elsevier. This book was released on 2015-11-29 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Strongly Interacting Quantum Systems out of Equilibrium written by Thierry Giamarchi and published by Oxford University Press. This book was released on 2016-07-07 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decade new experimental tools and theoretical concepts are providing new insights into collective nonequilibrium behavior of quantum systems. The exquisite control provided by laser trapping and cooling techniques allows us to observe the behavior of condensed bose and degenerate Fermi gases under nonequilibrium drive or after `quenches' in which a Hamiltonian parameter is suddenly or slowly changed. On the solid state front, high intensity short-time pulses and fast (femtosecond) probes allow solids to be put into highly excited states and probed before relaxation and dissipation occur. Experimental developments are matched by progress in theoretical techniques ranging from exact solutions of strongly interacting nonequilibrium models to new approaches to nonequilibrium numerics. The summer school `Strongly interacting quantum systems out of equilibrium' held at the Les Houches School of Physics as its XCIX session was designed to summarize this progress, lay out the open questions and define directions for future work. This books collects the lecture notes of the main courses given in this summer school.

Download or read book Rare Earths and Actinides in High Energy Spectroscopy written by Christiane Bonnelle and published by Springer. This book was released on 2015-12-22 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique monograph covers recent theoretical and experimental results on the complex character of f electrons in materials containing lanthanides (rare earths) or actinides, such as alpha-cerium and delta-plutonium. It answers the urgent need for a general presentation of the body of experimental and theoretical results presently available in this challenging domain. Some of the fast developing applications of lanthanide and actinide materials are mentioned. Materials containing atoms with an open f shell have electronic and crystalline properties that are controlled by the localized or delocalized character of the f electrons. This book gives a theoretical discussion of the various spectroscopic methods that shed light on the character of the f electrons and on the connection between their localization and the properties of these materials. Part 1 covers the characteristics of the f electrons in atoms and solids and includes a discussion of the properties of lanthanides and actinides in connection with the f electrons. Part 2 describes the various spectroscopic methods that are used to establish the electronic distributions and energies of the states. Examples involve the determination of f electron distributions by high energy spectroscopy methods with separate treatment of the valence and core electrons. Part 3 concentrates on the theoretical treatment of electronic transitions involving f electrons and simulations of the lanthanide spectra, including comparison with the available experimental data. Part 4 discusses the localized or delocalized character of the f electrons in actinides and their compounds, including comparison (analogies & differences) between the 4f and 5f electron materials. This monograph should be of great value for researchers, academics and engineers working in the fields of high energy spectroscopy, electronic and nuclear science and technology, as well as materials involving rare earths and radio-elements.

Download or read book Magnetism in Condensed Matter written by Stephen Blundell and published by OUP Oxford. This book was released on 2001-10-04 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: The superb book describes the modern theory of the magnetic properties of solids. Starting from fundamental principles, this copiously illustrated volume outlines the theory of magnetic behaviour, describes experimental techniques, and discusses current research topics. The book is intended for final year undergraduate students and graduate students in the physical sciences.

Download or read book High Magnetic Field Science and Its Application in the United States written by National Research Council and published by National Academies Press. This book was released on 2013-11-25 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Committee to Assess the Current Status and Future Direction of High Magnetic Field Science in the United States was convened by the National Research Council in response to a request by the National Science Foundation. This report answers three questions: (1) What is the current state of high-field magnet science, engineering, and technology in the United States, and are there any conspicuous needs to be addressed? (2) What are the current science drivers and which scientific opportunities and challenges can be anticipated over the next ten years? (3) What are the principal existing and planned high magnetic field facilities outside of the United States, what roles have U.S. high field magnet development efforts played in developing those facilities, and what potentials exist for further international collaboration in this area? A magnetic field is produced by an electrical current in a metal coil. This current exerts an expansive force on the coil, and a magnetic field is "high" if it challenges the strength and current-carrying capacity of the materials that create the field. Although lower magnetic fields can be achieved using commercially available magnets, research in the highest achievable fields has been, and will continue to be, most often performed in large research centers that possess the materials and systems know-how for forefront research. Only a few high field centers exist around the world; in the United States, the principal center is the National High Magnetic Field Laboratory (NHMFL). High Magnetic Field Science and Its Application in the United States considers continued support for a centralized high-field facility such as NHFML to be the highest priority. This report contains a recommendation for the funding and siting of several new high field nuclear magnetic resonance magnets at user facilities in different regions of the United States. Continued advancement in high-magnetic field science requires substantial investments in magnets with enhanced capabilities. High Magnetic Field Science and Its Application in the United States contains recommendations for the further development of all-superconducting, hybrid, and higher field pulsed magnets that meet ambitious but achievable goals.

Download or read book Stripes and Related Phenomena written by Antonio Bianconi and published by Springer Science & Business Media. This book was released on 2006-04-10 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of superconductors has been a central issue in Solid State Physics since 1987. After the discovery of superconductivity (HTSC) in doped perovskites, it was realized that the HTSC appears in an unknown complex electronic phase of c- densed matter. In the early years, all theories of HTSC were focused on the physics of a homogeneous 2D metal with large electron–electron correlations or on a 2D polaron gas. Only after 1990, a novel paradigm started to grow where this 2D metallic phase is described as an inhomogeneous metal. This was the outcome of several experimental evidences of phase separation at low doping. Since 1992, a series of conferences on phase separation were organized to allow scientists to get together to discuss the phase separation and related issues. Following the discovery by the Rome group in 1992 that “the charges move freely mainly in one direction like the water running in the grooves in the corrugated iron foil,” a new scenario to understand superconductivity in the superconductors was open. Because the charges move like rivers, the physics of these materials shifts toward the physics of novel mesoscopic heterostructures and complex electronic solids. Therefore, understanding the striped phases in the perovskites not only provides an opportunity to understand the anomalous metallic state of cuprate superconductors, but also suggests a way to design new materials of technological importance. Indeed, the stripes are becoming a field of general scientific interest.

Download or read book Thermal neutron scattering and critical magnetic fluctuations written by and published by . This book was released on 1970 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Superconductivity written by Karl-Heinz Bennemann and published by Springer Science & Business Media. This book was released on 2008-04-25 with total page 1568 pages. Available in PDF, EPUB and Kindle. Book excerpt: This extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in superconductivity. Covering the entire field, this unparalleled resource carefully blends theoretical studies with experimental results to provide an indispensable foundation for further research. Leading researchers, including Nobel laureates, describe the state of the art in conventional and unconventional superconductors. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued, intense research into electron-phone based superconductivity.

Download or read book The Role of Fluctuations Near Antiferromagnetic and Spin triplet Nematic Quantum Critical Points written by Gregor Maximilian Hannappel and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: