On the correlation of grain boundary misorientation distribution with critical current in bulk processed YBa2Cu3O7-delta

摘要

The grain boundary misorientation distribution of bulk processed high-ir, superconductor YBa2Cu3O7-delta was studied as a function of processing conditions. The deviation of the grain boundary misorientation distribution (GBMD) from the random distribution, was tested using a chi(2) analysis, and a grain boundary character distribution (GBCD) based upon the coincidence site lattice (CSL) model was developed and applied. The GBMD and GBCD both showed evolution departing from a random distribution for processing temperatures above 935 degrees C. The GBCD analysis suggests an increase in the population of CSL-related boundaries with annealing time and temperature; and, in particular, the population of boundaries related to CSLs derived from a crystal with c/a > 3 continued to increase with annealing, while the population of boundaries related to other CSLs (c/a = 3) remained essentially constant. Comparison of the GBCD with the volume-averaged J(c) for each processing condition, indicates that the increasing proportion of 'c/a > 3' boundaries is related to a reduction in J(c). [References: 41]