An Exponential Model for Critical Current Density Through a Low-Angle Grain Boundary in a High-T c Superconductor

Abstract

An analytical investigation is presented to display the distribution of critical current flow through a low-angle grain boundary in a high-T c superconductor such as YBCO or Bi-2212 film. When a superconductor is subjected to a transport current or a magnetic field, the fluxoids are redistributed between the dislocations which comprise a low-angle grain boundary. A model considering the elastic interaction between a flux line and an edge dislocation is developed in this paper. Results of our model are consistent with those of the classic exponential model, while for high-angle grain boundaries with the misorientation angles 𝜃 > 4∘, this model is invalid. It is helpful by using our model to understand the mechanisms of the effect of low-angle grain boundaries on critical current density.