Superconducting fluctuations and anomalous diamagnetism in underdoped YBa2Cu3O6+x from magnetization and 63Cu NMR-NQR relaxation measurements

Abstract

Magnetization and 63Cu NMR-NQR relaxation measurements are used to study the superconducting fluctuations in YBa2Cu3O6+x (YBCO) oriented powders. In optimally doped YBCO the fluctuating negative magnetization M_{fl}(H,T) is rather well described by an anisotropic Ginzburg-Landau (GL) functional and the curves M_{fl}/sqrt{H} cross at Tc. In underdoped YBCO, instead, over a wide temperature range an anomalous diamagnetism is observed, stronger than in the optimally doped compound by about an order of magnitude. The field and temperature dependences of M_{fl} cannot be described either by an anisotropic GL functional or on the basis of scaling arguments. The anomalous diamagnetism is more pronounced in samples with a defined order in the Cu(1)O chains. The 63Cu(2) relaxation rate shows little, if any, field dependence in the vicinity of the transition temperature Tc(H=0). It is argued how the results in the underdoped compounds can be accounted for by the presence of charge inhomogeneities, favoured by chains ordering.

References in corpus (10)

• Quasiparticle relaxation dynamics in superconductors with different gap structures: theory and experiments on YBa_{2}Cu_{3}O_{7-δ}
• Magnetic field independence of the spin gap in YBa_2Cu_3O_{7-delta}
• 3D-XY critical fluctuations of the thermal expansivity in detwinned YBa2Cu3O7-d single crystals near optimal doping
• Superconducting Fluctuation Effects on the Spin-Lattice Relaxation Rate in YBa_2Cu_3O_{6.95}
• Superconducting Magnetization above the Irreversibility Line in Tl2Ba2CuO6
• a-b plane optical conductivity in YBa_2Cu_3O_{7-delta} above and below T*
• Effects of Strong Magnetic Fields on Pairing Fluctuations in High Temperature Superconductors
• Crossovers and Phase Coherence in Cuprate Superconductors
• Regularization of the Density of States Fluctuation Contribution in Magnetic Field
• Superconducting Fluctuation Effects on the Electron Spin Susceptibility in YBa_2Cu_3O_{6.95}

Cited by in corpus (23)

• Inhomogeneous superconductivity and the "pseudogap state of novel superconductors
• Temperature range of superconducting fluctuations above T_c in YBa_2Cu_3O_{7-δ} single crystals
• Strongly nonlinear magnetization above $T_c$ in $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{r}}_2\mathrm{CaC}{\mathrm{u}}_2{\mathrm{O}}_{8+\delta }$
• Superconducting Fluctuations and the Pseudogap in the Slightly-overdoped High-Tc Superconductor TlSr2CaCu2O6.8: High Magnetic Field NMR Studies
• Thermodynamics of Gaussian fluctuations and paraconductivity in layered superconductors
• The in-plane paraconductivity in La_{2-x}Sr_xCuO_4 thin film superconductors at high reduced-temperatures: Independence of the normal-state pseudogap
• Anomalous precursor diamagnetism at low reduced magnetic fields and the role of Tc inhomogeneities in the superconductors Pb55In45 and underdoped La1.9Sr0.1CuO4
• Strong thermal fluctuations in cuprate superconductors in magnetic field above Tc
• Diamagnetism around the Meissner transition in a homogeneous cuprate single crystal
• The effects of magnetic field on the d-density wave order in the cuprates
• Developments in the negative-U modelling of the cuprate HTSC systems
• Structural and Tc inhomogeneities inherent to doping in La_{2-x}Sr_xCuO_4 superconductors and their effects on the precursor diamagnetism
• Fluctuating diamagnetism in underdoped high temperature superconductors
• Gossamer bulk high-temperature superconductivity in FeSe
• Conductivity of anisotropic inhomogeneous superconductors above critical temperature
• Fluctuation diamagnetism around the superconducting transition in a cuprate crystal with a reduced Meissner fraction
• The conductivity and the magnetization around Tc in optimally-doped YBa${}_2$Cu${}_3$O${}_{7-\delta }$ revisited: quantitative analysis in terms of fluctuating superconducting pairs
• Microscopic observation of superconducting fluctuations in $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Br by ${}^{13}$C NMR spectroscopy
• Non-conventional superconducting fluctuations in Ba(Fe1-xRhx)2As2 iron-based superconductors
• High-field muSR studies of superconducting and magnetic correlations in cuprates above Tc
• Observation of a common symmetry for the pseudogap and the superconducting order parameter near the surface of underdoped YBCO
• Diamagnetism, Nernst signal, and finite size effects in superconductors above the transition temperature
• Superconductivity at T=200K in Bismuth Cuprates Synthesized Using Solar Energy