Vortex pinning by a novel stress induced stacking fault microstructure in melt-textured YBa2Cu3O7

Transmission electron microscopy observations of melt-textured YBa2Cu3O7–Y2BaCuO5 composites deformed under uniaxial stress and a superposed gaseous confining pressure reveal the activation of a novel YBa2Cu4O8-type stacking fault source. This mechanism operates as a partial Frank Read source leading to small diameter (100–300 nm) loops. Jcab(T) dependences reveal a temperature dependent enhancement which is maximum at low temperatures, i.e., 45% at 5 K. A fit of Jcab(T) to a model that considers two contributions to Jc, namely correlated disorder and weak pinning, reveals that only the weak pinning contribution associated with the newly generated in-plane dislocation substructure is enhanced after deformation.