Low-Angle Grain Boundaries in YBa2Cu3O7-δ with High Critical Current Densities

Abstract

The grain boundary network in high-T_c coated conductors consists of a large number of low angle grain boundaries with many types of misorientation. Using the bicrystal technique we have measured the critical current densities of the relevant YBa₂Cu₃O_7-� grain boundary misorientations as a function of grain boundary angle. We find that in the low angle regime [010]-tilt boundaries and [100]-twist boundaries reduce the critical current density much less than [001]-tilt boundaries. Transmission electron microscopy reveals a low defect density in these boundaries and we find that CuO₂ planes cross these boundaries without interruption.