24 research outputs found
Doping effect on the evolution of the pairing symmetry in n-type superconductor near antiferromagnetic phase boundary
We present the investigation results of the in-plane \{rho}(T) resistivity
tensor at the temperature range 0.4-40 K in magnetic fields up to 90kOe (H||c,
J||ab) for electron-doped Nd{2-x}Ce{x}CuO{4+{\delta}} with different degree of
disorder near antiferromagnetic - superconducting phase boundary. We have
experimentally found that for optimally doped compound both the upper critical
field slope and the critical temperature decrease with increasing of the
disorder parameter (d-wave pairing) while in the case of the underdoped system
the critical temperature remains constant and (dHc2/dT)|Tc increases with
increasing of the disorder (s-wave pairing). These features suggest a possible
implementation of the complex mixture state as the (s+id)-pairing.Comment: 9 pages, 2 figure
The estimation of coherence length for electron-doped superconductor NdCeCuO
Results of low-temperature upper critical field measurements for
NdCeCuO single crystals with various and
nonstoichiometric disorder () are presented. The coherence length of
pair correlation and the product , where is the Fermi
wave vector, are estimated. It is shown that for investigated single crystals
parameter 100 and thus phenomenologically NdCeCuO - system
is in a range of Cooper-pair-based (BCS) superconductivity.Comment: 8 pages, 3 figures, 2 table
Anisotropic temperature dependence of normal state resistivity in underdoped region of a layered electron-doped superconductor Nd2- xCe x CuO4
The aim of this work is to investigate the temperature dependences both in CuO2 plane and out-of plane resistivities in electron-doped Nd2-xCexCuO4 for x from 0.135 up to 0.15 in order to analyze the anisotropy of the electrical transport in the process of the evolution from antiferromagnetic order in the underdoped region to superconducting order in optimally doped region. © 2018 Author(s)
Suppression of 2D superconductivity by the magnetic field: quantum corrections vs superconductor-insulator transition
Magnetotransport of superconducting Nd_{2-x}Ce_xCuO_{4+y} (NdCeCuO) films is
studied in the temperature interval 0.3-30 K. The microscopic theory of the
quantum corrections to conductivity, both in the Cooper and in the diffusion
channels, qualitatively describes the main features of the experiment including
the negative magnetoresistance in the high field limit. Comparison with the
model of the field-induced superconductor-insulator transition (SIT) is
included and a crossover between these two theoretical approaches is discussed.Comment: 5 pages, 4 figures. Submitted to JETP Letter
Resistivity tensor correlations in the mixed state of electron-doped superconductor Nd2-xCexCuO4+δ
The magnetic-field dependencies of the longitudinal and Hall resistance of the electron-doped compounds Nd2-xCexCuO4+δ in underdoped region with x = 0.14 and with varying degrees of disorder (δ) were investigated. It was established experimentally that the correlation between the longitudinal electrical resistivity and the Hall resistivity can be analyzed on the basis of scaling relationships: ρxy(B) ∼ [ρxx(B)]β. For the totality of the investigated single-crystal films of Nd2-xCexCuO4+δ/SrTiO3 the values of β from 0.8 to 1.55 is found. The observed feature in the electron-doped two-dimensional systems can be associated both with a displaying of anisotropic s - wave or d - wave pairing symmetry and with a pinning due to an essential degree of disorder in the samples under study. © 2016 Published by Elsevier B.V