Hall resistivity correlations in disordered electron-doped Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$ films

TL;DR

This study investigates the magnetic field dependence of resistivity tensor correlations in electron-doped Nd$_{2-x}$Ce$_x$CuO$_{4+ abla}$ films, revealing a transition from anisotropic s-wave to d-wave pairing symmetry near the phase boundary, influenced by disorder.

Contribution

It provides new insights into how disorder and doping levels affect the pairing symmetry and vortex dynamics in electron-doped cuprate superconductors.

Findings

The power-law exponent $eta$ decreases from 1.2 to 0.6 with doping.

Evidence of a transition from s-wave to d-wave pairing symmetry.

Disorder influences vortex motion and resistivity correlations.

Abstract

The resistivity tensor correlations $\rho_{xy}$($B$)$\sim$ $[\rho_{xx}(B)]^\beta$ for the mixed state magnetic field dependencies of the resistivity tensor of electron-doped Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$/SrTiO$_3$ single crystal films near the antiferromagnetic (AF) - superconducting (SC) phase transition and with varying degree of disorder ($\delta$) were studied. The decrease of $\beta$ from 1.2$\pm$0.2 at $x$ = 0.14 to 0.6$\pm$0.1 at $x$ = 0.15 points out on the evidence of the change from the anisotropic $s$ - wave to the $d$ - wave pairing symmetry in the external magnetic field at the transition from underdoped to optimally doped region. Peculiarities of the power law dependence of the vortex motion in the mixed state can be connected with some features of the nonstoichiometric disorder in layered electron-doped superconductors.