Browsing by Subject "High temperature superconductors"
Now showing items 1-11 of 11
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Article
Anisotropy of the resistivity in the a-b plane of a superconducting YBa2Cu3O7-δ single crystal
(1996)We have measured the in-plane longitudinal resistivities pa and pb as functions of temperature and magnetic field. The measurements were all made on the same detwinned single crystal of YBa2Cu3O7-δ (YBCO). Defining Tc to ...
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Conference Object
ARPES studies of the superconducting gap in high-temperature superconductors
(Affiliation: Argonne Natl. Lab. and Univ. of, Illinois/Chicago, Chicago, IL, USA, United StatesCorrespondence Address: Ding, H.Argonne Natl. Lab. and Univ. of, Illinois/Chicago, Chicago, IL, USAUnited States, 1996)Using high resolution angle-resolved photoemission spectroscopy (ARPES), we measure the superconducting gap and its momentum dependence in the high temperature superconductors Bi 2Sr 2CaCu 2O 8 (Bi2212) and YBa 2Cu 3O 6.95 ...
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Article
C-axis josephson tunneling between YBa2Cu3O7 − δ and Pb: Direct evidence for mixed order parameter symmetry in a high- Tc superconductor
(1997)C-axis Josephson tunneling experiments in which a conventional superconductor (Pb) is deposited across a single twin boundary of a YBa2Cu3O7 − δ (YBCO) crystal. We measure the critical current as a function of the magnitude ...
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Conference Object
Direct observation of microscopic inhomogeneities in high-Tc superconductors using energy-dispersive diffraction of synchrotron-produced xrays
(Affiliation: Naval Research Lab., Washington, DC,, USA, United StatesCorrespondence Address: Skelton, Earl F.Naval Research Lab., Washington, DC,, USAUnited States, 1995)Evidence of micron-sized structural inhomogeneities in several high transition temperature (T c) superconductors is presented. By illuminating samples with high energy, highly collimated x rays produced on a synchrotron ...
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Article
The effect of correlated and point defects on the vortex lattice melting transition in single-crystal YBa2Cu3O7-δ
(1994)The vortex melting transition Tm in several untwinned and twinned crystals is measured resistively in fields up to 8T. A Lindemann criterion for vortex lattice melting is obtained in addition to a sharp hysteresis in the ...
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Article
Experimental determination of the absolute temperature modulation in photothermal microscopy of Y1Ba2Cu3O7 crystals
(1997)We present a technique to experimentally determine the value of the temperature perturbation ST in photothermal microscopy. Knowledge of δT is necessary for proper analysis of the differential optical reflectivity (∂R/∂T) ...
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Article
Hall effect in detwinned single crystals of YBa2(Cu1-xZnx)3O7-δ in the mixed state
(1996)The effect of zinc doping on the mixed-state Hall effect in detwinned single crystals of YBa2Cu3O7-δ has been studied. We observe a sign reveral of the Hall effect in crystals with a superconducting transition temperature ...
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Article
A new kinetic term in the phenomenology of layered superconductors
(1993)We show that the Lawrence-Doniach free energy for layered superconductors can be derived from an anisotropic Ginzburg-Landau free energy with a spatially dependent coefficient for the quadratic term. Our derivation indicates ...
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Article
Photothermal measurements of differential reflectivity of YBCO related to the symmetry of the superconducting order parameter
(1996)We have investigated symmetry of the differential optical response of single YBCO domains in the a-b plane. As a function of temperature, this response consists of a smooth background and a sharp peak in the vicinity of ...
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Article
Sign reversal of the Hall effect in YBa2(Cu1-x)3O7-δ single crystals
(1995)We have measured the in-plane Hall effect and in-plane resistivity of cobalt-doped YBa2Cu3O7-δ (YBCO) single-crystal samples. The concentration of cobalt ranged from 1 to 3%. As the applied field was varied, a sign reversal ...
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Article
Symmetry of differential optical responses of normal and superconducting phases in single-crystal YBCO
(1995)We measured differential optical reflectivity (DOR) of YBCO single domains. DOR measurements reject the temperature independent bulk reflectivity and reveal dR dT. These measurements detect the superconducting transition, ...