Resistivity tensor correlations in the mixed state of electron-doped superconductor Nd2−x2−xCexCuO4+δ4+δ

• We have analyzed the varying degrees of disorder (δ  ) on the magnetic-field dependencies of the longitudinal and Hall resistance in electron-doped Nd2−x2−xCexCuO4+δ4+δ /SrTiO3 single crystal films (underdoped region with x = 0.14) near AF-SC phase boundary.
• The correlation between the longitudinal electrical resistivity and the Hall resistivity can be analyzed on the basis of scaling relationships: ρxy(B)∼ρxxβ(B).
• For a set of single-crystal films of Nd2−x2−xCexCuO4+δ4+δ /SrTiO3 the values of β   are 0.8–1.55. These values are substantially less than the theoretical value β=2β=2 predicted by a widely used phenomenological flux-flow model (especially for hole-doped HTS).
• In the most high-quality samples at lowest temperatures scaling exponent tends to distinct universal value, β=1,β=1, predicted theoretically by a model for clean d-wave superconductors. An increase in the degree of disorder, the temperature and/or magnetic field rise yield non universal values of β   higher than β=1β=1 (up to β   = (1.35 – 1.55)). A disorder in the studied samples may be associated both with the nonstoichiometric defects inherent to Nd2−x2−xCexCuO4+δ4+δ /SrTiO3 system and with the specialty of x = 0.14 underdoped compound disposed on a border of the antiferromagnetic and superconducting phases in electron-doped cuprate system.

The magnetic-field dependencies of the longitudinal and Hall resistance of the electron-doped compounds Nd2−x2−xCexCuO4+δ4+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−x2−xCexCuO4+δ4+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.