Effects of divalent impurities on the fluctuation conductivity of YBa 2 Cu 3 O 7 single crystals

2009 ◽  
Vol 404 (19) ◽  
pp. 3109-3112 ◽  
Author(s):  
V.N. Vieira ◽  
F.T. Dias ◽  
P. Pureur ◽  
J. Schaf
Keyword(s):  
Single Crystals ◽  
Fluctuation Conductivity

Fluctuation conductivity analysis for Bi2Sr2(Ca1−xYx)Cu2O8+δ single crystals in both overdoped and underdoped regimes

2007 ◽  
Vol 463-465 ◽  
pp. 126-130 ◽  
Author(s):  
Tatsunori Aoki ◽  
Yasushi Oikawa ◽  
Changman Kim ◽  
Takashi Tamura ◽  
Hajime Ozaki ◽  
...  
Keyword(s):  
Single Crystals ◽  
Fluctuation Conductivity

scholarly journals Peculiarities of pseudogap in Y0.95Pr0.05Ba2Cu3O7−δ single crystals under pressure up to 1.7 GPa

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. L. Solovjov ◽  
L. V. Omelchenko ◽  
E. V. Petrenko ◽  
R. V. Vovk ◽  
V. V. Khotkevych ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Hydrostatic Pressure ◽  
Single Crystal ◽  
Single Crystals ◽  
Temperature Interval ◽  
Fluctuation Theory ◽  
Structural Defects ◽  
Fluctuation Conductivity ◽  
First Time ◽  
Effect Of Hydrostatic Pressure

AbstractThe effect of hydrostatic pressure up to P = 1.7 GPa on the fluctuation conductivity σ′(T) and pseudogap ∆*(T) in Y0.95Pr0.05Ba2Cu3O7−δ single crystal with critical temperature Тс = 85.2 K (at P = 0) was investigated. The application of pressure leads to the increase in Tc with dTc/dP = +1.82 K∙GPa−1 while the resistance decreases as dlnρ(100 K)/dP = −(10.5 ± 0.2) %∙GPa−1. Regardless of the pressure, in the temperature interval from Tc to T0 (~88 K at P = 0) the behaviour of σ′(T) is well described by the Aslamazov – Larkin (AL – 3D) fluctuation theory, and above the T0 by the Lawrence – Doniach theory (LD). The Maki-Thompson (MT – 2D) fluctuation contribution is not observed. This indicates the presence of structural defects in the sample induced by Pr. Here it is determined for the first time that when the pressure is applied to the Y1−xPrxBa2Cu3O7−δ single crystal, the pseudogap increases as dlnΔ*/dP = 0.17 GPa–1.

scholarly journals Composition variation and electron irradiation effects on the fluctuation conductivity in Y1–zPrzBa2Cu3O7−δ single crystals

2020 ◽  
Vol 31 (21) ◽  
pp. 19429-19436
Author(s):  
A. Chroneos ◽  
D. D. Kolesnikov ◽  
I. A. Taranova ◽  
A. V. Matsepulin ◽  
R. V. Vovk
Keyword(s):  
Single Crystals ◽  
Oxygen Deficiency ◽  
High Energy ◽  
Superconducting Transition ◽  
Crossover Point ◽  
Fluctuation Conductivity ◽  
High Energy Electrons ◽  
Composition Variation ◽  
Temperature Dependences ◽  
Different Temperatures

AbstractA comparative analysis of the changes in the fluctuation conductivity and characteristics of the superconducting state of YBa2Cu3O7–δ single crystals caused by various types of defects is carried out. These defects appeared due to irradiation with high-energy electrons (radiation doses from 1.4 to 8.8 1018 cm–2), changes in oxygen deficiency (0.08 ≤ δ ≤ 0.23) due to annealing at different temperatures, or doping with praseodymium (Y1–zPrzBa2Cu3O7−δ, 0 ≤ z ≤ 0.5 at optimal oxygen concentration). It is shown that the introduction of such defects leads to a significant expansion of the temperature range of the existence of excess conductivity, and upon doping with praseodymium, it also leads to the appearance of a thermally activated deflection on the temperature dependence of the electrical resistance. The effect of such defects on the superconducting transition temperature, Tc, and the coherence length along the c axis, ξc(0), is studied. In particular, ξc(0) more than quadruples (at z = 0.43), while the 2D-3D crossover point shifts towards higher temperatures. Possible reasons for the suppression of superconductivity in YBa2Cu3O7–δ upon irradiation with fast electrons and the qualitatively different temperature dependences of its resistivity in the basal plane, ρab (T), are discussed.

Effect of high pressure on the fluctuation conductivity and the charge transfer of YBa2Cu3O7−δ single crystals

2008 ◽  
Vol 453 (1-2) ◽  
pp. 69-74 ◽  
Author(s):  
R.V. Vovk ◽  
M.A. Obolenskii ◽  
A.A. Zavgorodniy ◽  
A.V. Bondarenko ◽  
I.L. Goulatis ◽  
...  
Keyword(s):  
High Pressure ◽  
Charge Transfer ◽  
Single Crystals ◽  
Fluctuation Conductivity

Electron irradiation and annealing effects on the pseudogap in optimally doped YBCO single crystals

2020 ◽  
Vol 34 (14) ◽  
pp. 2050151
Author(s):  
G. Ya. Khadzhai ◽  
R. V. Vovk ◽  
S. F. Zdorovko ◽  
A. Chroneos
Keyword(s):  
Single Crystals ◽  
Mean Field Theory ◽  
Mean Field ◽  
Excess Conductivity ◽  
Fluctuation Conductivity ◽  
Fast Electrons ◽  
Exponential Temperature Dependence ◽  
Annealing Effects ◽  
The Mean ◽  
Field Transition

The effect of room-temperature annealing on the basal-plane conductivity of YBCO single crystals is investigated after their irradiation with fast electrons. It is revealed that the excess conductivity [Formula: see text] of the samples obeys an exponential temperature dependence in a broad temperature range [Formula: see text]. Here, [Formula: see text] is the crossover temperature from the pseudogap to the fluctuation conductivity regime. The description of the excess conductivity with the expression [Formula: see text] can be interpreted in terms of the mean-field theory where [Formula: see text] corresponds to the mean-field transition temperature to the pseudogap state and the dependence [Formula: see text] is described within the framework of the BCS-BEC crossover theory.

Conductivity anisotropy in Y1-yPryBa2Cu3O7-δ single crystals in a wide range of praseodymium concentrations

2014 ◽  
Vol 28 (31) ◽  
pp. 1450245 ◽  
Author(s):  
Ruslan V. Vovk ◽  
Georgij Ya. Khadzhai ◽  
Oleksandr V. Dobrovolskiy
Keyword(s):  
Temperature Dependence ◽  
Single Crystals ◽  
Coherence Length ◽  
Conductivity Anisotropy ◽  
Fluctuation Conductivity ◽  
Metallic Conductivity ◽  
Variable Range ◽  
Wide Range ◽  
The Ideal

Anisotropies of different conductivity mechanisms in Y 1-y Pr y Ba 2 Cu 3 O 7-δ single crystals in a wide range of praseodymium concentrations are reported, assuming a transition from the metallic conductivity to the semiconductor-like regime, in conjunction with the fluctuation conductivity within the 3D Aslamazov–Larkin model. The Tc anisotropy grows with increasing y, with a most drastic rise when approaching the non-superconducting composition. As the praseodymium concentration increases, the ideal resistance anisotropy passes through a maximum at y ≈ 0.19. The temperature dependence of the semiconductor-like resistance anisotropy exhibits a maximum associated with variable-range jumps along the c-axis. The temperature dependence of the fluctuation conductivity anisotropy passes through a maximum due to a significant anisotropy of the coherence length.

Two-dimensional superconductivity of SmFeAsO0.85 single crystals: A fluctuation-conductivity study

2010 ◽  
Vol 470 ◽  
pp. S422-S423
Author(s):  
Hyun-Sook Lee ◽  
Jae-Hyun Park ◽  
Jae-Yeap Lee ◽  
Ju-Young Kim ◽  
Nak-Heon Sung ◽  
...  
Keyword(s):  
Single Crystals ◽  
Two Dimensional ◽  
Fluctuation Conductivity
Sign in / Sign up

Export Citation Format

Share Document