Investigation of phase-slip-like resistivity in underdoped YBCO

Abstract

We investigated the anomalous peak resistivity below the onset $T_c$ in underdoped YBCO, reminiscent of that observed in 1D wires of conventional superconductors. We performed measurements of the angular dependence of resistivity $\rho (\theta )$ in a magnetic field and the temperature dependence of resistivity $\rho (T)$, which exhibit a peak for $\text{B}\parallel$ ab-planes. This peak in $\rho (T)$ disappears for $\text{B}\parallel$ c-axis. The width of the corresponding maximum in $\rho (\theta )$ at $\theta =0^o$ ($\text{B}\parallel$ ab-planes) decreases with increasing c-axis component of the field ($B\sin \theta$). The maximum in $\rho (\theta )$ and $\rho (T)$ decreases with an increasing applied transport current. We analyzed the data using three different models of resistivity based on 2D resistor array, flux motion, and thermally activated phase-slips. Numerical calculations suggest that in a filamentary underdoped system, the phase-slip events could produce the anomalous resistivity close to $T_c$.

26 pages with 10 figures, submitted to PRB