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Resistivity tensor correlations in the mixed state of electron-doped superconductor Nd$_{2-x}$Ce$_x$CuO$_{4+δ}$

The magnetic-field dependencies of the longitudinal and Hall resistance of the electron-doped compounds Nd$_{2-x}$Ce$_x$CuO$_{4+δ}$ 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: $ρ_{xy}$($B$)$\sim$ $ρ^β_{xx}$($B$). For the totality of the investigated single-crystal films of Nd$_{2-x}$Ce$_x$CuO$_{4+δ}$/SrTiO$_3$ the universal value $β$=1.5 $\pm$0.4 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 rather strong pinning due to an essential degree of disorder in the samples under study.