Critical Current Density Through Grain Boundaries in High-Temperature Superconductors

In this paper, a theoretical study is proposed based on the assumption that the vortices on low-angle grain boundaries (GBs) in high-temperature superconductor (HTS) are mixed Abrikosov-Josephson (AJ) vortices. The critical current density through GB is obtained on the basis of the Bean critical model and the assumption that the periods of AJ vortices coincide with the ones of Abrikosov (A) vortices. The model also enables us to calculate J (c) of HTS with an inclined GB. In addition, the effect of strain on critical current density is also taken into account in this model by considering the strain dependence of deparing current density within GB. There is a good agreement of our results with the classical power-law expression. The model proposed in this work can be used for simultaneous studies of the effects of misorientation angles, GB-inclined angles, and applied fields on the critical current density of polycrystalline HTS.