19 Result(s)
within
Conference Paper
Setsuko Tajima
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Chapter and Conference Paper
Vortex Lattice Melting in Underdoped YBa2Cu4O8
Vortex lattice melting of YBa2Cu4O8 (Y124) crystals has been investigated by means of the bulk measurements. The vortex lattice softening as a precursor to the first-order melting transition can clearly be seen i...
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Chapter and Conference Paper
Incommensurate Spin Fluctuations in YBCO — Charge and Spin Stripe Scenario —
A brief summary of the recent inelastic neutron scattering studies on spin dynamics of the superconducting YBCO is given. Spin fluctuations in CuO2 plane was experimentally shown to be of the incommensurate (IC) ...
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Chapter and Conference Paper
Josephson Plasma Reflectivity Edge in Pb-doped Bi2212 Single Crystals: Direct Evidence for Reduced Anisotropy of Bi2212 by Pb-do**
We have successfully observed, for the first time, the Josephson plasma reflectivity edge of Bi-based high-T c cuprate using carrier overdoped Bi(Pb)2212 single crystal (T c = 65 K...
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Chapter and Conference Paper
Resonant Raman Scattering in Twin-Free YBa2(Cu1-xZnx)3O7-δ Single Crystals
The Resonant Raman scattering spectra of twin-free YBa2(Cu1-xZnx)3O7-δ single crystals with optimal oxygen content have been investigated in a temperature range from 300 to l0K in the xx- and yy-polarizations. To...
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Chapter and Conference Paper
Anisotropy of Underdoped YBa2Cu3O6.5 Single Crystal
The c-axis anisotropy of an underdoped YBa2Cu306.5 single crystal has been investigated by the torque magnetometry. The underdoped crystal shows a superconducting transition at 60 K. The torque was measured upon ...
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Chapter and Conference Paper
Role of Intrinsic Pinning for Melting Transition of YBa2Cu3O6.93 in the Parallel Field to CuO2 Layers
Vortex lattice melting of an untwinned YBa2Cu3O6.93 single crystal has been investigated by means of the ac susceptibility and the torque. The crystal shows the vortex-lattice-melting transition in H||c configura...
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Chapter and Conference Paper
Separation of Electronic and Phononic Components in Raman Spectra of High-Tc Superconductors
We demonstrate the inadequacy of the widely-used “standard Fano procedure” (deconvolution of a spectrum into a Fano profile and an incoherent background), and its main alternative, which is based on Green-func...
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Chapter and Conference Paper
Behavior of “Forbidden” Modes in Raman Spectra of Underdoped YBa2Cu3O7-X
Polarized phononic Raman scattering spectra of underdoped YBa2Cu3O7-X (x=0.2-0.4) single crystals have been investigated as a function of the excitation laser wavelength and temperature. Besides five dominating A
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Chapter and Conference Paper
Flux Pinning Property in Y-123 Single Crystal
The longitudinal and transverse flux bundle sizes are estimated for a three-dimensional single crystal Y-123 superconductor under a magnetic field along the c-axis and the result is compared with previous results...
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Chapter and Conference Paper
On the Origin of Peak Effect in High-Tc Superconductors
The origin of the peak effect in high-Tc superconductors is argued to be closely linked with the fundamental transformation between vortex solid and vortex liquid. The peak appears and grow when the transition...
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Chapter and Conference Paper
Vortex Lattice Melting in Untwinned Single Crystal YBa2Cu3O7 When Fields Are Applied Parallel to CuO2 Plane
Vortex lattice melting of a large untwinned YBa2Cu3O7 single crystal, prepared by a pulling technique, has been investigated by means of the ac susceptometer and the SQUID magnetometer in the field of 0–50 kG. Th...
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Chapter and Conference Paper
Manifestation of oxygen-ordering kinetics in Raman spectra of YBa2Cu3O7-x single crystals
We have studied temporal changes in Raman scattering spectra of YBa2Cu3O7-x (x=0.2-0.6) single crystals and found in spectra clear evidence for a reversible oxygen redistribution under exposure of polarized laser...
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Chapter and Conference Paper
Impurity (Ni,Zn) Effects on Resistive Broadening in YBa2Cu3Oy Crystals
Zn-/Ni- substituted YBa2Cu3Oy single crystals were grown by a crystal pulling method, and their resistivities in magnetic field have been investigated. We have observed that a gross feature of the resistive broad...
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Chapter and Conference Paper
Detwinning and Retwinning of YBa2Cu3O7-δ Single Crystals with Variable Oxygen Stoichiometry
The single-crystal susceptibility and magnetization hysteresis of YBa2Cu3O7 and YBaCu3O6.6 with Tc’s of 90K and 58K, respectively, were measured on the twin-free samples. The detwnning and retwinning processes ar...
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Chapter and Conference Paper
The Change of Electron Density from YBa2Cu3O6 to Twin-free YBa2Cu3O6.9 Single Crystals
The electron density maps of YBa2Cu3O6 (YBCO6) and twin-free orthorhombic YBa2Cu3O69 (YBCO69) single crystals were calculated from the refinement of X-ray structure analysis. The YBCO7-x single crystal was grown ...
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Chapter and Conference Paper
The Superconducting Properties of YBCO Single Crystal Prepared by Crystal Pulling
We present anisotropic transport properties for YBa2Cu3O7-δ single crystal prepared by the pulling method. The resistivity in the ab-plane (ρab), for both the as-grown sample and the oxygen annealed sample, show ...
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Chapter and Conference Paper
Correlation Between Crystal Structure and Irreversibility Magnetic Fields in Oxide and Organic Superconductors
We have considered a correlation between the superconducting interlayer (d) of crystal structure and irreversibility magnetic fields (H*) in 2D- superconductors including oxide and organic superconductors. In ...
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Chapter and Conference Paper
Electronic States of High-Tc Cuprates Investigated by Optical Measurements
Based on the optical spectra, the electronic states of the high-Tc cuprates are discussed. In the high-Tc superconductivity composition, the charge transfer gap is almost completely destroyed, resulting in the...
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Chapter and Conference Paper
Phonons in (Sm,Ce)2(Ba,Sm)2Cu3Ox
Polarized Raman spectra of (Sm,Ce)2(Ba,Sm)2Cu3Ox which has Cu-O5 pyramid structure as well as YBa2Cu3O7 have been measured at room temperature using single crystals. Peaks have been observed at 442 and 537 cm−1 i...
