Phase-slip-like resistivity in underdoped YBa₂Cu₃O₇

We investigated the anomalous peak resistivity below the onset T_c in underdoped YBa₂Cu₃O₇, reminiscent of that observed in one-dimensional (1D) wires of conventional superconductors. We performed measurements of the angular dependence of resistivity ρ(θ) in a magnetic field and the temperature dependence of resistivity ρ(T), which exhibit a peak for B‖ ab planes. This peak in ρ(T) disappears for B‖ c axis. The width of the corresponding maximum in ρ(θ) at θ=0° (B‖ ab planes) decreases with the increasing c-axis component of the field (Bsinθ). The maximum in ρ(θ) and ρ(T) decreases with an increasing applied transport current. We analyzed the data using three different models of resistivity based on a 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 an anomalous resistivity close to T_c.