Experimental search for anisotropic flux flow resistivity in the a-b plane of optimally doped epitaxial thin films of YBCO

TL;DR

This study investigates flux flow resistivity anisotropy in YBCO thin films and finds no significant directional difference, challenging assumptions about flux pinning related to the d-wave order parameter.

Contribution

It provides the first experimental comparison of flux flow resistivity along different crystallographic directions in YBCO thin films.

Findings

Flux flow resistivity is isotropic within experimental error.

No correlation between flux pinning and d-wave symmetry observed.

Results suggest flux pinning properties are direction-independent in YBCO.

Abstract

Transport measurements along the node and anti-node directions in the a-b plane of optimally doped and epitaxial thin films of YBCO are reported. Low bias magnetoresistance measurements near and below T_c show that the flux flow resistivity along the node and anti-node directions versus magnetic field are indistinguishable. This result suggests that within the experimental error of our measurements, no correspondence is found between the flux pinning properties in YBCO and the d-wave nature of the order parameter.