The Influence of Grain Boundary Roughness on Tricrystal Symmetry Tests

Abstract

Phase sensitive experiments in tricrystal grain boundary samples[1, 2, 3, 4, 5, 6] have demonstrated that a number of the high-Tc cuprate superconductors have predominantly d-wave symmetry. The reproducibility of these experiments is remarkable, when one considers the roughness of the grain boundary interfaces. Here we briefly describe how this roughness affects the magnetic properties of grain boundaries in high-Tc superconductors. We then describe experiments designed and performed to make conclusive symmetry tests despite this roughness.