24 Result(s)
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Article
High Frequency Transport Properties of YBCO: Extrinsic Versus Intrinsic d-Wave Properties
In good superconducting YBCO films, the surface impedance Z(T,ω,B)=Zint(T,ωB)+Zres(T,ωB) is dominated for T T c/2 and B∼0 by intrinsic properties, which are difficult to improve. B...
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Article
Metal-Insulator Transition (MIT), Defects, and Percolative Transport in HTS
HTS as layered, doped Mott insulators close to the Metal-Insulator Transition (MIT) become insulating at 6.5 kΩ per CuO-plane at n L ≤ 1021/cm3 localized states. The MIT occurs exponentially around point defects ...
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Article
Corrosion and surface spectroscopies of high-temperature superconductors
Crucial spectroscopic high-temperature superconductor (HTS) information is based on surface methods, like scanning tunneling spectroscopy (STS) or angle-resolved photo-emission spectroscopy (ARPES). But, typic...
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Article
Pseudogap and Transport in HTS
Perpendicular transport is one of the key factors to HTS superconductivity, sampling the quasi-insulating blocking layer, separating the conducting CuO-planes, and driving the metal–insulator transition (MIT) ...
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Article
Charge transfer via interfaces, especially of nanoscale materials
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Article
Resonant Tunneling, Pseudo-Gap, and Charge Dynamics in Cuprate Superconductors
The quasi-two-dimensional, metallic conduction in the CuO2 planes and activated out-of-plane conduction seem typical for most of the cuprate superconductors. The counteraction of overlap and charging energies ΔU*...
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Article
Tunnel channels, spectroscopy and imaging in STM
φ/?≈5.1/nmfor a tunnel with barrier height φ≈1 eV are given for surfaces covered by water, air or vacuum. Despite the n=1,2,3 intermediate states and their charging, imaging down to atomic resolution is achiev...
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Article
YBa2Cu3O7-δ single crystals revisited: Scanning probe data on very pure samples grown in BaZrO3 crucibles
Cu3O7-δ (YBCO) single crystals grown in BaZrO3 crucibles by scanning and friction force microscopy (SFM, FFM) as well as by scanning tunneling microscopy (STM) and angle resolved X-ray photo-electron spectroscopy...
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Article
Nonlinear surface impedance in “low” and “high”T c superconductors
The degradation of the surface impedanceZ = R + iX with rf power is a principal limit for measurements and applications. Such nonlinearities occur for normal conducting cavities by heating or electron loading. Bu...
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Article
Resonant tunneling and perpendicular conduction in cuprate conductors with varying O-content
Anisotropy is inherent to layered cuprates with conduction mainly confined to the CuO2-planes, claimed to be the source of superconductivity. Resonant tunnel exchange for conduction parallel and perpendicular to ...
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Article
Temperature dependence of surface impedance Z(T, ω) and mean free paths I(T) of YBCO-superconductors
The surface impedance Z(T,ω) at 10 and 145 GHz and between 4 and 300 K is obtained experimentally. Z(Ta≤T≤Tc) is quantitatively fitted by the BCS theory with a mean free path I(T) increasing rapidely below Tc. Th...
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Article
Granular superconductors and their intrinsic and extrinsic surface impedance
High-frequency experiments depend sensitively on homogeneous and inhomogeneous “defects” in the normal and superconducting state. As homogeneous effects, the intrinsic scattering time is of great theoretical i...
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Article
On intrinsic and extrinsic effects in the surface impedance of cuprate superconductors
Surface impedance measurements in the normal and superconducting state are an excellent method to study conduction electron dynamics and extended defects. Electron dynamics show up most clearly in the relaxati...
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Article
Submillimeter surface impedance and relaxation: A case study of quasi-two-dimensional YBa2Cu3Ox
Surface impedance measurements in the normal and superconducting state are an excellent method to study the conduction electron dynamics in metals. This holds especially in the relaxation range, i.e., for dist...
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Article
The surface impedance of superconductors and normal conductors: The Mattis-Bardeen theory
The contribution of the Mattis-Bardeen theory to the understanding of the surface impedance of superconductors and normal conductors is reviewed. The early theoretical and experimental studies of the surface i...
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Chapter
Mutual Inductance of Thin Film Pb-Bi-Sr-Ca-Cu-O Films
The standard diagnostic for determining the superconducting transition temperatures of thin films is the resistivity-temperature (R-T) measurement. These resistivity measurements are made as a function of temp...
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Chapter
Rf Residual Losses, Surface Impedance and Granularity in Superconducting Cuprates
The rf residual surface resistance Rres is a figure of merit for superconducting microwave devices and for the homogeneity of superconducting surfaces. In granular superconductors not only high Rres values but al...
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Chapter
Weak Links and Planar Defects in Superconducting Cuprates
In the new cuprate superconductors weak links are the reasons for deterioration of the -super- conducting properties. These weak links are classified according to their conductivity. indicating that insulating...
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Article
Analysis of the dc-resistivity of YBa2Cu3Ox: Deduction of the intragrain resistivity
The resistivity ρ(100 K) scatters very much for YBa2Cu3Ox prepared as single crystals, epitaxial films or bulk samples which consist of grains of 1 to 10 μm diameter. An analysis of ρ(T) for granular bulk samples...
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Article
ARXPS-studies ofĉ-axis textured — superconducting YBa2Cu3O x -films
YBa2Cu3O x sputter deposited cold on Al2O3 and on MgO grows in O2 annealing epitaxially to a transparent, superconducting film withT c=80 K. The unscraped surfaces of these film...
