Download or read book Charge Stripes and Local Structural Inhomogeneities in La2 subscript X Sr Ba subscript X CuO4 High Temperature Superconductors written by Emil S. Bozin and published by . This book was released on 2003 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Superconductivity and Structure in La sub 2 x M subscript X CuO4 M written by and published by . This book was released on 2000 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The identification of charge stripes in La{sub 2-x-y}Nd{sub y}Sr(subscript x)CuO4 (Nd-214) has reenergized research on the original high transition temperature {Tc} superconductor, La{sub 2-x}Ba(subscript x)CuO4 (Ba-214), and related compounds. Early in the study of Ba-214, a low temperature phase transition was associated with changes in electrical properties. An apparent suppression of {Tc} near Ba x=0.125, was initially associated with a first order low temperature phase transformation. However, it was later shown that only very near Ba x=0.125 was {Tc} reduced markedly, and that the relationship between crystal structure and {Tc} is more complicated. This review well describe the low temperature crystal structures and microstructures, as well as the superconducting properties as determined from low field (1-100G) dc magnetometer measurements for Ba-214, Nd-214, and La{sub 2-x}Sr(subscript x)CuO4 (Sr-214). The authors will also describe some work in the related La{sub 2-x}Ca(subscript x)CuO4 (Ca-214). A basic knowledge of the interactions among superconductivity and low temperature phases will allow one to better understand the significance of the underlying charge stripe phases.
Download or read book Local Structure and Superconductivity in La sub 2 x Ba subscript X CuO4 for X written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reviews our recent work on characterising the structural and electronic transitions in La{sub 2-x}Ba(subscript x)CuO4. This is a high-temperature superconductor which shows interesting an interesting interrelationship between structure and atomic properties. We have used x-ray and neutron diffraction to characterize the structure and show tat the current understanding of the structural phase transitions, and their relationship to the superconductivity, is incomplete.
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 Electronic Properties of High temperature Superconductors written by Brent Armand Richert and published by . This book was released on 1989 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Charge Stripes and Spin Correlations in Copper oxide Superconductors written by and published by . This book was released on 1997 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: To obtain superconductivity in a layered copper-oxide compound, it is necessary to introduce charge carriers into the antiferromagnetic CuO2 planes. Recent neutron diffraction studies of the system La{sub 1.6-x}Nd{sub 0.4}Sr(subscript x)CuO4 provide evidence that the dopant-induced holes choose to segregate into periodically-spaced stripes which separate antiferromagnetic domains, in a manner similar to that found in hole-doped La2NiO4. The charge and spin stripe modulations are identified by the appearance of scattering at incommensurate positions. In the Nd-doped system, elastic scattering is observed, corresponding to static stripes. In pure La{sub 2-x}Sr(subscript x)CuO4, the magnetic scattering that is observed is purely inelastic. Where samples with and without Nd, but with the same Sr concentration, have been measured, the incommensurate (IC) splittings of the magnetic signal are found to be essentially identical. It has been proposed that the spin correlations in the two systems are fundamentally the same, thus implying similar charge correlations. The static nature of the stripes in the Nd-doped system is attributed to pinning of the otherwise dynamic correlations by a special distortion of the lattice. That distortion is driven by purely ionic interactions and is stabilized by the smaller ionic radius of the substituted Nd.
Download or read book Superconductivity and Structure in La sub 2 x MxCuO4 M written by and published by . This book was released on 2000 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The identification of charge stripes in La{sub 2-x-y}Nd{sub y}SrxCuO4 (Nd-214) has reenergized research on the original high transition temperature {Tc} superconductor, La{sub 2-x}BaxCuO4 (Ba-214), and related compounds. Early in the study of Ba-214, a low temperature phase transition was associated with changes in electrical properties. An apparent suppression of {Tc} near Ba x=0.125, was initially associated with a first order low temperature phase transformation. However, it was later shown that only very near Ba x=0.125 was {Tc} reduced markedly, and that the relationship between crystal structure and {Tc} is more complicated. This review well describe the low temperature crystal structures and microstructures, as well as the superconducting properties as determined from low field (1-100G) dc magnetometer measurements for Ba-214, Nd-214, and La{sub 2-x}SrxCuO4 (Sr-214). The authors will also describe some work in the related La{sub 2-x}CaxCuO4 (Ca-214). A basic knowledge of the interactions among superconductivity and low temperature phases will allow one to better understand the significance of the underlying charge stripe phases.
Download or read book Theory of Copper Oxide Superconductors written by Hiroshi Kamimura and published by Springer. This book was released on 2010-10-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an advanced textbook for graduate students and researchers wishing to learn about high temperature superconductivity in copper oxides, in particular the Kamimura-Suwa (K-S) model. Because a number of models have been proposed since the discovery of high temperature superconductivity by Bednorz and Müller in 1986, the book first explains briefly the historical development that led to the K-S model. It then focuses on the physical background necessary to understand the K-S model and on the basic principles behind various physical phenomena such as electronic structures, electrical, thermal and optical properties, and the mechanism of high temperature superconductivity.
Download or read book Visualising the Charge and Cooper Pair Density Waves in Cuprates written by Stephen Edkins and published by Springer. This book was released on 2017-08-31 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports on the use of scanning tunnelling microscopy to elucidate the atomic-scale electronic structure of a charge density wave, revealing that it has a d-symmetry form factor, hitherto unobserved in nature. It then details the development of an entirely new class of scanned probe: the scanning Josephson tunnelling microscope. This scans the Josephson junction formed between a cuprate superconducting microscope tip and the surface of a cuprate sample, thereby imaging the superfluid density of the sample with nanometer resolution. This novel method is used to establish the existence of a spatially modulated superconducting condensate, something postulated theoretically over half a century ago but never previously observed.
Download or read book Structural Relationships in High Temperature Superconductors written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent discovery of two types of metallic copper oxide compounds which are superconducting to above 90°K has renewed interest in the search for new high temperature superconducting materials. It is significant that both classes of compounds, La/sub 2-x/Sr(subscript x)CuO/sub 4-y/ and YBa2Cu3O/sub 7-delta/ are intimately related to the extensively studied perovskite family. Both compounds contain highly oxidized, covalently bonded Cu-O sublattices, however, they differ in geometry. In this paper we discuss the relationship of these features to the superconducting properties. 30 refs., 6 figs.
Download or read book Synthesis and Superconducting Properties of the High Transition Temperaure i e Temperature Superconductor Ba1 subscript X K subscript X BiO3 written by Timothy John Folkerts and published by . This book was released on 1990 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Suppression of Superconductivity in Orthorhombic La sub 2 x M subscript X CuO4 M written by and published by . This book was released on 1994 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have extended the calcium solid-solubility limit in La{sub 2-x} Ca(subscript x)CuO4 to x = 0.2 using synthesis at high oxygen pressure. The superconducting transition temperature increases with doping to 34 K at x = 0.15 and is suppressed for x> 0.15, similar to the Sr-substituted material. At a fixed doping level, the optimum superconducting properties (the highest {Tc}) are found for flat and square CuO2planes.
Download or read book Transport Properties and Upper Critical Fields of Single Crystals in the Superconducting System Y subscript 1 x Pr subscript X Ba2Cu3O subscript 7 delta written by YueXian Jia and published by . This book was released on 1992 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electronic Structure of La Sr 2CuO4 and Ba sub 0 6 K sub 0 4 BiO3 written by and published by . This book was released on 1994 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured and calculated the electron-positron momentum distribution of La{sub 2-x}Sr(subscript x)CuO4 samples for Sr concentration of 0, 0.1,0.13, and 0.2 and Ba{sub 0.6}K{sub 0.4}BiO3. The momentum distribution of all samples contained features derived from the overlap of the positron distribution with the valence electrons. In addition, discontinuities typical of a Fermi surface are seen in the superconducting samples. The form and position of these features are in general agreement with band theory for both La{sub 2-x}Sr(subscript x)CuO4 and Ba{sub 0.6}K{sub 0.4}BiO3. However, the evolution of the Fermi surface with doping in La{sub 2-x}Sr(subscript x)CuO4 differed significantly from expectations based on single electron band theories.
Download or read book Compilation of NRL Publications on High Temperature Superconductivity written by Donald U. Gubser and published by . This book was released on 1987 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Partial contents: Superconducting Phase Transitions in the La-M-Cu-O Layered Perovskite System, M = La, Ba Sr, and Pb; Temperature Dependent X-Ray Studies of the High T sub c Superconductor La(1.9)Ba(0.1)CuO4; X-Ray Identification of the Superconducting High T sub c Phase in the Y-Ba-Cu-O System; Processing and Properties of the High T sub c Superconducting Oxide Ceramic YBasub2Cu3O7; Phonon Density of States and Structure of the Superconductor YBasub2Cu3O7; Magnetic Field Studies of the La(2-x)MxCuO4 and Ba2Y1Cu3O7 High T sub c Superconductors; Preparation, Structure, and Magnetic Field Studies of High T sub c Superconductors; Electronic Structure, Bonding and Electron-Phonon Interaction in La-Ba-Cu-O Superconductors; Band Theory Analysis Of Anisotropic Transport in La2CuO4-Based Superconductors; Prediction of Anisotrophic Thermopower of La(2-x)MxCuO4; Character of States Near the Fermi Level in YBa2Cu3O7; Complex Hamiltonians: Common Features of Mechanisms of High-T sub c and Slow Relaxation; Plasma Sprayed Superconducting Oxide Coatings; Resonant Photoemission Study of Superconducting Y-Ba-Cu-O; Observed Trends in the X-Ray Photoelectron and Auger Spectra of High Temperature Superconductors; and Impact of High-Temperature Superconductors on High Power, Millimeter Wave Source Technology.
Download or read book The Growth and Elastoresistance Measurement of FeTe1 xSex written by Yue Shi and published by . This book was released on 2018 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The iron-based superconductors (FeSCs) is one of the only two high temperature superconductors. Soon after its discovery, mounting experiments performed on several families of FeSCs demonstrate the existence of an electronic driven broken rotational symmetry phase, the nematic phase. As an integral part of the phase diagram, understanding the nature of the nematic phase is a key step to unveil the origin of high temperature superconductivity. The underlying charge or spin degree of freedom responsible for the nematic transition might be the same degree of freedom that gives rise the superconductivity and magnetic order. In this thesis, we use the elastoresistance technique to probe the nematic fluctuations in iron chalcogenide superconductors FeTe[subscript]1-xSe[subscript]x, which is one of the prototypes of FeSCs with the simplest crystal structure. Specifically, two unique features of FeTe[subscript]1-xSe[subscript]x distinguish it from the well-studied iron pnictides. First, the bicollinear antiferromagnetic order in FeTe is different from the collinear antiferromagnetic order in iron pnictides. Second, the nematic phase in FeSe forms without magnetic ordering, which is not the case in iron pnictides. Consequently, a systematic study of the FeTe[subscript]1-xSe[subscript]x family will provide important insights into the universal role played by the nematic fluctuations. In my thesis, I first describe the synthesis and annealing procedures of FeTe[subscript]1-xSe[subscript]x crystals. Then I introduce the theoretical background and experimental techniques of elastoresistance measurement for B[subscript]2g symmetry channel of Tetragonal symmetry point group. Finally, I describe the measurement of strong nematic fluctuation in FeTe[subscript]1-xSe[subscript]x. Our results show that the nematic fluctuations increase as the Se doping concentration increase for FeTe[subscript]1-xSe[subscript]x (x = 0 - 0.5). The sign of elastoresistivity coefficient 2m66 flips between the FeTe0.8Se0.2 and FeTe0.7Se0.3 from negative to positive. The bare nematic critical temperature T* extracted from the Curie-Weiss fitting of 2m66 are negative for all components measured in our experiments. With the Se doping concentration increase, the bare nematic critical temperature T* approaches to zero, which implies the existence of nematic quantum criticality at the optimally doping.
Download or read book Thermodynamic Critical Field and Superconducting Fluctuation of Vortices for High Temperature Cuprate Superconductor La 214 written by Yung Moo Huh and published by . This book was released on 2001 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: The La[Subscript 2-x]Sr[Subscript x]Cu0[Subscript 4] (La-214) system displays the fluctuating vortex behavior with the characteristic of either 2D or 3D fluctuations as indicated by clearly identifiable crossing points T* close to Tc. The dimensional character of the fluctuations depends on both applied magnetic fields and the density of charge carriers. The dimensional crossover from 2D to 3D occurs in the strongly underdoped regime when the c-axis coherence distance [Xi]c becomes comparable to the spacing between adjacent CuO2 layers s at sufficiently high magnetic fields near Hc2.
