The critical current of YBa2Cu3O7-d Low Angle Grain Boundaries

TL;DR

This study investigates how the critical current in YBa2Cu3O7-delta thin film grain boundaries varies with magnetic field orientation, revealing flux cutting effects at high fields and specific angular suppression.

Contribution

It provides new insights into the angular dependence of critical current in low-angle grain boundaries, applying a flux cutting model to describe the behavior.

Findings

Critical current is strongly suppressed within a specific angular range at fields above 1 T.

Outside this range, the grain boundary's critical current is dominated by the grains.

Flux cutting model accurately describes the angular dependence of critical current in the suppressed region.

Abstract

Transport critical current measurements have been performed on 5 degree [001]-tilt thin film YBa2Cu3O7-delta single grain boundaries with magnetic field rotated in the plane of the film, phi. The variation of the critical current has been determined as a function of the angle between the magnetic field and the grain boundary plane. In applied fields above 1 T the critical current, j_c, is found to be strongly suppressed only when the magnetic field is within an angle phi_k of the grain boundary. Outside this angular range the behavior of the artificial grain boundary is dominated by the critical current of the grains. We show that the phi dependence of j_c in the suppressed region is well described by a flux cutting model.