Vortex state in YBa2Cu3Oy crystals: vortex phase diagram and tunneling spectroscopy in magnetic field

2004 ◽  
Vol 346-347 ◽  
pp. 329-333 ◽  
Author(s):  
N. Kobayashi ◽  
T. Nishizaki ◽  
K. Shibata ◽  
T. Sasaki
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Vortex State ◽  
Tunneling Spectroscopy ◽  
Vortex Phase Diagram ◽  
Vortex Phase

Flux Dynamics and Vortex Phase Diagram in Tl2Ba2CaCu2O8 System

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3423-3426
Author(s):  
P. Chowdhury ◽  
Heon-Jung Kim ◽  
Sung-Ik Lee
Keyword(s):  
Phase Diagram ◽  
Activation Barrier ◽  
Vortex State ◽  
Physical Parameters ◽  
Flux Dynamics ◽  
Single Vortex ◽  
Vortex Phase Diagram ◽  
Vortex Phase ◽  
Second Peak ◽  
Peak Field

Experimental data on the field and time dependencies of the isothermal magnetization hysteresis for Tl 2 Ba 2 CaCu 2 O 8 single crystals with fields applied parallel to the c-axis are reported. From the M–H measurements, we determined the first peak field (Hp), the onset field of the second peak (Hon), the second peak field (Hsp), and the irreversible field (Hirr). Using these physical parameters, we have drawn a vortex phase diagram for this system. As observed in BSCCO(2212) system, below the irreversibility line, the H–T plane is divided into three distinct phases: the vortex lattice, the entangle phase, and the quasi 2D pancake vortex states in the temperature interval 30 K ≤T≤60 K .1 From the relaxation of remanent magnetization measurements, we have obtained the flux creep activation barrier U(j) as a function of j using the method developed by Malay et al. Within the collective pinning theory, it is argued that T≤30 K , the pancake vortices are pinned individually, while for T≥42 K , the vortex state is characterized by individually pinned 3D vortex strings. At T~30 K , a crossover from 2D pancake to 3D collectively pinned state was observed and shows a smooth crossover to 3D single vortex state at higher temperatures.

The activation energy U(T,B) in high temperature superconductor

2020 ◽  
Vol 92 (2) ◽  
pp. 20601
Author(s):  
Abdelaziz Labrag ◽  
Mustapha Bghour ◽  
Ahmed Abou El Hassan ◽  
Habiba El Hamidi ◽  
Ahmed Taoufik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Activation Energy ◽  
Phase Diagram ◽  
High Temperature ◽  
Apparent Activation Energy ◽  
High Temperature Superconductor ◽  
Flux Flow ◽  
Resistivity Measurements ◽  
Vortex Phase ◽  
The Magnetic Field

It is reported in this paper on the thermally assisted flux flow in epitaxial YBa2Cu3O7-δ deposited by Laser ablation method on the SrTiO3 substrate. The resistivity measurements ρ (T, B) of the sample under various values of the magnetic field up to 14T in directions B∥ab-plane and B∥c-axis with a dc weak transport current density were investigated in order to determine the activation energy and then understand the vortex dynamic phenomena and therefore deduce the vortex phase diagram of this material. The apparent activation energy U0 (B) calculated using an Arrhenius relation. The measured results of the resistivity were then adjusted to the modified thermally assisted flux flow model in order to account for the temperature-field dependence of the activation energy U (T, B). The obtained values from the thermally assisted activation energy, exhibit a behavior similar to the one showed with the Arrhenius model, albeit larger than the apparent activation energy with ∼1.5 order on magnitude for both cases of the magnetic field directions. The vortex glass model was also used to obtain the vortex-glass transition temperature from the linear fitting of [d ln ρ/dT ] −1 plots. In the course of this work thanks to the resistivity measurements the upper critical magnetic field Hc2 (T), the irreversibility line Hirr (T) and the crossover field HCrossOver (T) were located. These three parameters allowed us to establish a phase diagram of the studied material where limits of each vortex phase are sketched in order to optimize its applicability as a practical high temperature superconductor used for diverse purposes.

Vortex phase diagram in heavy ion irradiated untwinned YBa2Cu3Oy single crystals

2007 ◽  
Vol 460-462 ◽  
pp. 1204-1205 ◽  
Author(s):  
Norio Kobayashi ◽  
Terukazu Nishizaki ◽  
Kuniaki Kasuga ◽  
Satoru Okayasu
Keyword(s):  
Phase Diagram ◽  
Single Crystals ◽  
Heavy Ion ◽  
Vortex Phase Diagram ◽  
Vortex Phase

Vortex Phase Diagram in Bi2Sr2CaCu2O y , Probed by ac-Susceptibility Measurements

1999 ◽  
pp. 621-624
Author(s):  
Takao Sasagawa ◽  
Toshiya Fujita ◽  
Hisashi Kobayashi ◽  
Jun-Ichi Shimoyama ◽  
Koichi Kitazawa ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Ac Susceptibility ◽  
Vortex Phase Diagram ◽  
Vortex Phase

Resistivity measurements and the vortex phase diagram of Bi2Sr2CaCu2O y

1996 ◽  
Vol 105 (5-6) ◽  
pp. 1189-1194 ◽  
Author(s):  
H. Ikuta ◽  
S. Watauchi ◽  
J. Shimoyama ◽  
K. Kitazawa ◽  
K. Kishio
Keyword(s):  
Phase Diagram ◽  
Resistivity Measurements ◽  
Vortex Phase Diagram ◽  
Vortex Phase
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