Enhanced current flow through meandering grain boundaries in y Ba2 Cu3 O7-δ films

Abstract

In Y Ba2 Cu3 O7-δ (YBCO) coated conductors grown by metal organic deposition, in-plane meandering of grain boundaries (GBs) has been linked to higher critical current density. The authors investigate this link in individual GBs using transport measurements and scanning Hall probe microscopy with current reconstruction. They observe current-induced flux entry into a coated conductor, then model its behavior by imaging YBCO films with single, straight GBs tilted at various angles to the applied current. They find a strong dependence of critical current on angle, sufficient to explain the enhancement observed for meandering GBs. © 2007 American Institute of Physics.